Compiled Clinical Chemistry quizzes BS Medical Technology (De La Salle Medical and Health Sciences Institute)

Analytes elevated in the morning: * Chloride, phosphorus, potassium and amylase Lactic acid, creatine kinase ACTH, cortisol, iron and aldosterone ACP, growth hormone, PTH and TSH Pipets are used with biologic fluids having a viscosity greater than that of water: * Mohr pipets Ostwald−Folin pipets Pasteur pipets Volumeteric pipets Analytes elevated when in standing position: * Glucose, insulin, triglycerides, gastrin and ionized calcium ACTH, cortisol and catecholamines Lactic acid, ammonia and blood gases Albumin, cholesterol, aldosterone and calcium Most basic pipette: * Automatic pipette Glass pipette Ratio: ROUTINELY USED: automatic pipette MOST BASIC: glass pipette Does not have graduations to the tip: * Mohr pipet Serologic pipet Micropipet None of these Ratio: A Mohr pipet does not have graduations to the tip.It is a self-draining pipet, but the tip should not be allowed to touch the vessel while the pipet is draining. Pipette with BULB CLOSER TO THE DELIVERY TIP and are used for accurate measurement of VISCOUS FLUIDS, such as blood or serum: * Ostwald−Folin pipette Volumetric pipette Pipette with cylindrical glass bulb near the CENTER of the pipette that helps to distinguish them from other types of transfer pipettes. * Ostwald−Folin pipette Volumetric pipette Extremely inert, excellent temperature tolerance and chemical resistance; used for stir bars, stopcocks and tubing: * Polyethylene Polycarbonate Polystyrene Teflon Ratio: POLYETHYLENE  Widely used in plastic ware, too, including test tubes, bottles, graduated tubes, stoppers, disposable transfer pipets, volumetric pipets, and test tube racks.  May bind or absorb proteins, dyes, stains, and picric acid POLYCARBONATE  Used in tubes for centrifugation, graduated cylinders, and flasks  Usable temperature range is broad: –100° C to +160° C  Very strong plastic but is not suitable for use with strong acids, bases, and oxidizing agents  May be autoclaved but with limitations POLYSTYRENE  Rigid, clear type of plastic that should not be autoclaved  Used in an assortment of tubes, including capped graduated tubes and test tubes  Not resistant to most hydrocarbons, ketones, and alcohols TEFLON  Widely used for manufacturing stirring bars, tubing, cryogenic vials, and bottle cap liners  Almost chemically inert and is suitable for use at temperatures ranging from –270° C to +255° C  Resistant to a wide range of chemical classes, including acids, bases, alcohol, and hydrocarbons Horizontal−head centrifuge: * Cytocentrifuge Fixed−angle head centrifuge Swinging bucket centrifuge Ultracentifuge Ratio: HORIZONTAL-HEAD OR SWINGING BUCKET CENTRIFUGE * HORIZONTAL WHEN MOVING OR SPINNING * VERITICAL WHEN NOT MOVING Cups holding the tubes of material to be centrifuged occupy a vertical position when the centrifuge is at rest but assume a horizontal position when the centrifuge revolves It is used when rapid centrifugation of solutions containing small particles is needed; an example is the microhematocrit centrifuge: * Horizontal−head centrifuge Fixed−angle head centrifuge Ultracentrifuge Cytocentrifuge High−speed centrifuges used to separate layers of different specific gravities, commonly used to separate lipoproteins: * Horizontal−head centrifuge Fixed−angle head centrifuge Ultracentrifuge Cytocentrifuge Ratio: ULTRACENTRIFUGE High-speed centrifuges used to separate layers of different specific gravities Commonly used to separate lipoproteins Usually refrigerated to counter heat produced through friction Uses a very high−torque and low−inertia motor to spread MONOLAYER OF CELLS rapidly across a special slide for critical morphologic studies: * Horizontal−head centrifuge Fixed−angle head centrifuge Ultracentrifuge Cytocentrifuge Ratio: CYTOCENTRIFUGE Uses a very high-torque and low-inertia motor to spread monolayers of cells rapidly across a special slide for critical morphologic studies Used for blood, urine, body fluid, or any other liquid specimen that can be spread on a slide Calibration of centrifuges is customarily performed every . * Daily Weekly Every 3 months (quarterly) Yearly Ratio: Photoelectric tachometer or strobe tachometer CAP recommends that the number of revolutions per minute for a centrifuge used in chemistry laboratories be checked every 3 months Centrifuges are routinely disinfected on a basis. * Daily Weekly Monthly Quarterly Water produced using either an anion or a cation EXCHANGE RESIN, followed by replacement of the removed ions with hydroxyl or hydrogen ions. * Deionized water Distilled water RO water The PUREST TYPE OF REAGENT WATER is: * HIGHLY PURIFIED SUBSTANCES of a known composition: Control Standard It represents a specimen that is SIMILAR IN COMPOSITION TO THE PATIENT’S WHOLE BLOOD or plasma: * Control Standard Type I Type II Type III All are equal Ratio: Chemicals that are used to manufacture drugs: * Technical or commercial grade Analytical grade Ultrapure grade USP and NF chemical grade Ratio: o It is important for qualitative and quantitative analyses; essential for accuracy. o Specifications were established by the American Chemical Society (ACS). o Labels on these reagents either state the actual impurities for each chemical lot or list the maximum allowable impurities (percentage impurities). Use: trace metal analysis and preparation of standard solutions o These types of reagents have been put through additional purification steps. o Suitable for techniques that require extremely pure chemicals o These reagents may carry designations of HPLC or chromatographic on their labels. o Example: Spectrogade, nanograde and HPLC pure o Use: chromatography, atomic absorption and immunoassays  Chemically Pure (CP) or Pure Grade o The impurity limitations of this type of chemical are usually not stated – it fails to reveal the tolerance limits of impurities. o Preparation of these chemicals is not uniform. o Purity is usually delivered by measurement of melting point or boiling point. o It is not recommended for research and analytical chemistry unless further purification or a reagent blank is included.  Technical or Commercial Grade o It is used primarily in manufacturing. o It should never be used in clinical laboratory testing.  United States Pharmacopoeia (USP) and National Formulary (NF) o It is approved for human consumption (not injurious to individuals) but may be applicable for laboratory analysis. o Use: drug manufacturing Basic unit for mass: * Gram Kilogram Mole Pound Ratio: BASE QUANTITY 1. Length (meter) 2. Mass (kilogram) 3. Time (second) 4. Electric current (ampere) 5. Thermodynamic temperature (Kelvin) 6. Amount of substance (mole) 7. Luminous intensity (Candela) Equal parts per hundred or the amount of solute per 100 total units of solution: * Dilution Molarity Normality Percent solution Ratio: Concentration or normality. olution o Expressed as equal parts per hundred or the amount of solute per 100 total units of solution. A percent solution can be described as: (1) w/w, which is expressed as weight (mass) per 100 units of weight (g/g). (2) w/v, which is expressed as weight (mass) per 100 units of volume (g/dL). (3) v/v, which is expressed as volume (mL) per unit of volume (mL) Molarity o It is expressed as the number of moles per 1 L of solution. One mole of a substance equals its gram molecular weight. o It represents the amount of solute per 1 kg of solvent. o It is defined as the number of grams equivalent weights per liter of solution. o An equivalent weight is equal to gmw of a substance divided by its valence. o Valence is the number of units that can combine with or replace 1 mole of hydrogen ions for acids and hydroxyl ions for bases and the number of electrons exchanged in oxidation−reduction reactions. Which of the following is NOT A COLLIGATIVE PROPERTY of solutions? Electrical equipment fire: * Class A Class B Class C Class D pH Freezing point Osmotic pressure Vapor pressure Ratio: The properties of osmotic pressure, vapor pressure, freezing point, and boiling point are called COLLIGATIVE PROPERTIES. When a solute is dissolved in a solvent, these colligative properties change in a predictable manner for each osmole of substance present:  FREEZING POINT IS LOWERED by −1.86°C  VAPOR PRESSURE IS LOWERED by 0.3 mm Hg or torr  OSMOTIC PRESSURE IS INCREASED by a factor of 1.7 × 104 mm Hg or torr  BOILING POINT IS RAISED by 0.52°C BIOSFAETY CABINET: 30% recirculated, 70% exhausted. BSC Class II B1 Type of extinguisher for CLASS A FIRES: 1. Pressurized water 2. Dry chemical 3. Carbon dioxide 4. Halon * 1 and 2 1 and 3 1, 2 and 3 Only 1 Ratio: TYPE OF EXTINGUISHER (Bishop page 47) Class A: Pressurized water and dry chemical Class B: Dry chemical and carbon dioxide Class C: Dry chemical, carbon dioxide and halon Class D: Metal X All of the following are CROYEGENIC MATERIALS HAZARDS, EXCEPT: * Asphyxiation Fire or explosion Shock Tissue damage similar to thermal burns Ratio: Liquid nitrogen is probably one of the most widely used cryogenic fluids (liquefied gases) in the There are, however, several hazards associated with the use of any cryogenic material: fire or explosion, asphyxiation, pressure buildup, embrittlement of materials, and tissue damage similar to that of thermal burns. Repetitive strain disorders such as tenosynovitis, bursitis, and ganglion cysts: * Cryogenic materials hazards Electrical hazards Ergonomic hazards Mechanical hazards When a person is receiving an electrical shock, all of the following should be done EXCEPT: Pull the person away from the electrical source Turn off the circuit breaker Move the electrical source using a glass object Move the electrical source using a wood object Ratio: When an accident involving electrical shock occurs: The electrical source must be removed immediately. TURNING OFF THE CIRCUIT BREAKER, UNPLUGGING THE EQUIPMENT, or moving the equipment using a nonconductive glass or wood object are safe procedures to follow. Most common source of light for work in the visible and near−infrared regions: * Deuterium discharge lamp and mercury arc lamp Incandescent tungsten or tungsten−iodide lamp Ratio: The most common source of light for work in the visible and near-infrared regions is the incandescent tungsten or tungsten-iodide lamp. The lamps most commonly used for ultraviolet (UV) work are: * Deuterium discharge lamp and mercury arc lamp Incandescent tungsten or tungsten−iodide lamp The first step to take when attempting to repair electronic equipment is to: * Check all electronic connections Turn instrument off and unplug it Reset all the printed circuit boards Review instrument manual Ratio: Before REPAIR OR ADJUSTMENT of electrical equipment The following should be done (1) unplug the equipment (2) make sure the hands are dry (3) remove jewelry. Ratio; The lamps most commonly used for ultraviolet (UV) work are the deuterium discharge lamp and the mercury arc lamp. Which is the most sensitive detector for spectrophotometry? * Photomultiplier Phototube Electron multiplier Photodiode array Ratio; Because of this amplification, the PM tube is 200 times more sensitive than the phototube. PM tubes are used in instruments designed to be extremely sensitive to very low light levels and light flashes of very short duration. Reflectance spectrometry uses which of the following? Luminometer Tungsten–halogen lamp Photomultiplier tube UV lamp Thermometer to monitor temperature in reaction Low temperature: Increase in fluorescence Decrease in fluorescence Liquids (reagents, diluents, and samples) are pumped through a system of [continuous] tubing: * Continuous flow analysis Centrifugal analysis Discrete analysis None of these Which of the following light sources is used in atomic absorption spectrophotometry? * Hollow−cathode lamp Xenon arc lamp Tungsten light Deuterium lamp Laser Ratio: The usual light source, known as a hollow- cathode lamp, consists of an evacuated gas-tight chamber containing an anode, a cylindrical cathode, and an inert gas, such as helium or argon. Used to measure concentration of LARGE PARTICLES: Which of the following types of analyzers offers RANDOM−ACCESS CAPABILITIES? * Discrete analyzers Continuous−flow analyzers Centrifugal analyzers None of these Ratio: All three can use batch analysis (i.e., large number of specimens in one run), but only discrete analyzers offer random-access, or stat, capabilities. 2. Turbidimetry 3. Absorption spectroscopy * 1 only 2 only 1 and 2 1, 2 and 3 Temperature is proportional to fluorescence. * Directly proportional Inversely proportional No effect Measures of center. * Mean Median Mode Measures of spread. * Coefficient of variation Range Standard deviation Systematic errors include: Deterioration of reagents Improper calibration Improper mixing of sample and reagent Instrument drift Mislabeling a sample Pipetting errors Most frequently occurring value in a dataset: * Mean Median Mode Range Ratio: The mode is the most frequently occurring value in a dataset. Although it is seldom used to describe data, it is referred to when in reference to the shape of data, a bimodal distribution, for example. Type of systemic error in the sample direction and magnitude; the magnitude of change is constant and not dependent on the amount of analyte. * Constant systematic error Proportional systematic error Ratio: Constant error: Type of systemic error in the sample direction and magnitude; the magnitude of change is constant and not dependent on the amount of analyte. Type of systemic error where the magnitude changes as a percent of the analyte present; error dependent on analyte concentration. * Constant systematic error Proportional systematic error Difference between the observed mean and the reference mean: * Bias Confidence interval Parametric method Nonparametric method Ability of a test to detect a given disease or condition. * Analytic sensitivity Analytic specificity Diagnostic sensitivity Diagnostic specificity Ratio: Analytic sensitivity: Ability of a method to detect small quantities of an analyte. Analytic specificity: Ability of a method to detect only the analyte it is designed to determine. Diagnostic sensitivity: Ability of a test to detect a given disease or condition. Diagnostic specificity: Ability of a test to correctly identify the absence of a given disease or condition. Proportional error: Type of systemic error where the magnitude changes as a percent of the analyte present; error dependent on analyte concentration. Ability of a test to correctly identify the absence of a given disease or condition. * Analytic sensitivity Analytic specificity Diagnostic sensitivity Diagnostic specificity Ability of a method to detect small quantities of an analyte. * Analytic sensitivity Analytic specificity Diagnostic sensitivity Diagnostic specificity Ability of a method to detect only the analyte it is designed to determine. * Analytic sensitivity Analytic specificity Diagnostic sensitivity Diagnostic specificity Positive predictive value: * Ability of a test to detect a given disease or condition. Ability of a test to correctly identify the absence of a given disease or condition. Chance of an individual having a given disease or condition if the test is abnormal. Chance an individual does not have a given disease or condition if the test is within the reference interval. Negative predictive value: * Ability of a test to detect a given disease or condition. Ability of a test to correctly identify the absence of a given disease or condition. Chance of an individual having a given disease or condition if the test is abnormal. What percentage of values will fall between ±2 s in a Gaussian (normal) distribution? 34.13% 68.26% 95.45% 99.74% Two (2) consecutive control values exceed the same 2 standard deviation limit: * 1:2S 2:2S R:4S 4:1S Ratio: Westgard multirule is a control procedure that utilizes control rules to assess numerical quality control data; the control rules establish the limits for data rejection in a system with two controls. Other rules apply when three controls are used. 1:2s = 1 control value exceeds the mean ±2 standard control values using the other rejection rules that follow; only rule that is not used to reject a run; results are reportable 1:3s = 1 control value exceeds the mean ±3 standard deviations; detects random error 2:2s = 2 consecutive control values exceed the same 2 standard deviation limit (same mean +2 s or same mean -2 s); detects systematic error R:4s = 1 control value in a group exceeds the mean +2 s and a second control value exceeds the mean -2 s, creating a 4 standard deviation spread; detects random error 4:ls = 4 consecutive control values are recorded on one side of the mean and exceed either the same mean +1 s or the same mean -1 s; detects systematic error 10:x =10 consecutive control values are recorded on one side of the mean (either above or below the mean); detects systematic error The term R:4S means that: * Four consecutive controls are greater than ±1 standard deviation from the mean Two controls in the same run are greater than 4s units apart Two consecutive controls in the same run are each greater than ±4s from the mean There is a shift above the mean for four consecutive controls Ratio: The R:4s rule is applied to two control levels within the same run. The rule is violated when the algebraic difference between them (level 1 – level 2) exceeds 4s. The R:4s rule detects random error (error due to poor precision). Error always in one direction: * Random error Systematic error Which of the following terms refers to deviation from the true value caused by indeterminate errors inherent in every laboratory measurement? * Random error Standard error of the mean Parametric analysis Nonparametric analysis Ratio: Random errors are deviations from the true value caused by unavoidable errors inherent in laboratory measurements. The standard error of the mean is a statistical concept reflecting sampling variation. It is the standard deviation of the entire population. Parametric statistics refer to a Gaussian (normal) distribution of data. Nonparametric statistics are more general and require no assumptions. A trend in QC results is most likely caused by: * Deterioration of the reagent Miscalibration of the instrument Improper dilution of standards Electronic noise Which of the following would result in a sudden shift in daily values on a quality control chart? * Recalibrating the instrument when changing reagent lot numbers during an analytical run Replacing the instrument's sample aspiration probe Changing the spectrophotometer lamp in the middle of a sample run Changing personnel operating the instrument Which of the following plots is best for detecting all types of QC errors? * Levy–Jennings Tonks–Youden Cusum Linear regression Which of the following plots is best for comparison of precision and accuracy among laboratories? * Levy–Jennings Tonks–Youden Cusum Linear regression Which of the following terms refers to the closeness with which the measured value agrees with the true value? * Random error Precision Accuracy Variance Ratio: The accuracy of an analytical result is the closeness with which the measured value agrees with the true value. Precision is reproducibility. Accuracy and precision are independent, but it is the goal of the clinical laboratory to design methods that are both precise and accurate. Relatively easy to measure and maintain: * Accuracy Precision Sensitivity Specificity Which plot will give the earliest indication of a shift or trend? * Levy–Jennings Tonks–Youden Cusum Histogram Ratio: Accuracy is easy to define but difficult to establish and maintain. Precision is relatively easy to measure and maintain. Which of the following describes the ability of an analytical method to maintain both accuracy and precision over an extended period of time? * Reliability Validity Probability Sensitivity Ratio: The reliability of an analytical procedure is its ability to maintain accuracy and precision over an extended period of time during which supplies, equipment, and personnel in the laboratory may change. It is often used interchangeably with the term "consistency." It is the goal of every clinical laboratory to produce reliable results. Which of the following statistical tests is used to compare the means of two methods? * Student’s t test F distribution Correlation coefficient (r) Linear regression analysis Insulin is the primary hormone responsible for the entry of glucose into the cell. LACK OF INSULIN = Impaired entry of glucose into the cell. * ANOTHER CLARIFICATION: ACTION OF INSULIN: increases glycogenesis and glycolysis; increases lipogenesis and decreases glycogenolysis. INSULIN INCREASES GLYCOGENESIS, GLYCOLYSIS AND LIPOGENESIS; DECREASES GLYCOGENOLYSIS. Please check Sir KR's discussion today for his clarification. Salamat. * FROM SIR KR, PLEASE CORRECT YOUR NOTES. Ostwald-Folin transfer pipettes - To differentiate this type of pipette from a volumetric transfer pipette, there is a rounded bulb that is positioned CLOSER TO THE DELIVERY TIP. * −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Which of the following is the most common application of IMMUNOELECTROPHORESIS (IEP)? * Identification of the absence of a normal serum protein Structural abnormalities of proteins Screening for circulating immune complexes Diagnosis of monoclonal gammopathies PRE−ECLAMPSIA, also referred to as TOXEMIA OF PREGNANCY is marked by specific symptoms including: Water retention (with swelling particularly in the feet, legs, and hands) High blood pressure Protein in the urine All of these A sensitive, although not specific indicator of damage to the kidneys: * Urea Creatinine Proteinuria Cystatin C At pH 8.6, proteins are charged and migrate toward the . * For albumin assay, absorbance at 630 nm is less likely to be affected by bilirubin or hemoglobin in the sample. Which dye gives a much greater absorbance change at 630 nm than it would at 500 nm? * HABA (Hydroxyazobenzene−benzoic acid) BCG (Bromcresol green) Which of the following dyes is the MOST SPECIFIC for measurement of albumin? * Bromcresol green (BCG) Bromcresol purple (BCP) Tetrabromosulfophthalein Tetrabromphenol blue Ratio: BCP is more specific for albumin than BCG. In what condition would an increased level of serum albumin be expected? * Malnutrition Acute inflammation Dehydration Renal disease ARTIFACTUAL INCREASE in albumin concentration: * Negatively, anode Positively, cathode Positively, anode Negatively, cathode Prolonged tourniquet application Dehydration Nephrotic syndrome Inflammation Identification of which of the following is useful in early stages of glomerular dysfunction? * Microalbuminuria Ketonuria Hematuria Urinary light chains Most abundant amino acid in the body: * Glutamine Lysine Phenylalanine Tyrosine Ratio: Glutamine is the most abundant amino acid in the body, being involved in more metabolic processes than any other amino acid. Precursor of the adrenal hormones epinephrine, norepinephrine, and dopamine and the thyroid hormones, including thyroxine: * Glutamine Lysine Phenylalanine Tyrosine Sensitive marker of poor nutritional status: * Prealbumin Fibrinogen Gc−globulin Orosomucoid Ratio: A low prealbumin level is a sensitive marker of poor nutritional status. When a diet is deficient in protein, hepatic synthesis of proteins is reduced, with the resulting decrease in the level of the proteins originating in the liver, including prealbumin, albumin, and β-globulins. Because prealbumin has a short half-life of approximately 2 days, it decreases more rapidly than do other proteins. Nutritional assessment with poor protein−caloric status is associated with: * A decreased level of prealbumin A low level of γ−globulins An elevated ceruloplasmin concentration An increased level of α1−fetoprotein Retinol (vitamin A) binding protein: * Albumin Alpha1−antitrypsin Fibronectin Prealbumin The plasma protein mainly responsible for maintaining colloidal osmotic pressure in vivo is: * Albumin Hemoglobin Fibrinogen Alpha2−macroglobulin Ratio: Prealbumin is the transport protein for thyroxine and triiodothyronine (thyroid hormones); it also binds with retinol-binding protein to form a complex that transports retinol (vitamin A) and is rich in tryptophan. Which of the following conditions is the result of a LOW ALPHA1−ANTITRYPSIN LEVEL? * Asthma Emphysema Pulmonary hypertension Sarcoidosis All are conditions associated with an elevated AFP, EXCEPT: * Neural tube defects Spina bifida Anencephaly Down syndrome Which of the following is a low−weight protein that is found on the cell surfaces of nucleated cells? * Alpha2−macroglobulin Beta2−microglobulin C−reactive protein Ceruloplasmin Ratio: Conditions associated with an elevated AFP level include spina bifida, neural tube defects, abdominal wall defects, anencephaly (absence of the major portion of the brain), and general fetal distress. Low levels of maternal AFP indicate an increased risk for Down syndrome and trisomy 18, while it is increased in the presence of twins and neural tube defects. In nephrotic syndrome, the levels of serum may increase as much as 10 times because its large size aids in its retention. * Alpha2−macroglobulin Ceruloplasmin Orosomucoid Transferrin Ratio: In nephrosis, the levels of serum α2- macroglobulin may increase as much as 10 times because its large size aids in its retention. The protein is also increased in diabetes and liver disease. Use of contraceptive medications and pregnancy increase the serum levels by 20%. Orosomucoid: * Alpha1−antitrypsin Alpha1−chymotrypsin Alpha1−fetoprotein Alpha1−acid glycoprotein Ratio: β2-microglobulin is a single polypeptide chain that is the light chain component of human leukocyte antigens (HLAs). It is found on the surface of nucleated cells and is notably present on lymphocytes. Increased plasma levels of β2- microglobulin are associated with renal failure, lymphocytosis, rheumatoid arthritis, and systemic lupus erythematosus. Variants demonstrate a wide variety of cellular interactions, including roles in cell adhesion, tissue differentiation, growth, and wound healing: * Beta−trace protein Cystatin C Fibronectin Troponin A glycoprotein used to help predict the short−term risk of PREMATURE DELIVERY: * Adiponectin Alpha−fetoprotein Amyloid Fetal fibronectin BIOCHEMICAL MARKER OF BONE RESORPTION that can be detected in serum and urine: * Beta−trace protein Crosslinked C−telopeptides (CTX) Fibronectin Troponin An accurate marker of CSF leakage: * Beta−trace protein Crosslinked C−telopeptides (CTX) Fibronectin Troponin Rattio: β-Trace protein (BTP; synonym prostaglandin D synthase) is a 168–amino acid, low-molecular-mass protein in the lipocalin protein family. Recently, it was verified that BTP was established as an accurate marker of CSF leakage. It has also been reported recently as a potential marker in detecting impaired renal function, although no more sensitive than cystatin C. Recently proposed new marker for the early assessment of changes to the glomerular filtration rate: * Adiponectin Beta−trace protein Cross−linked C−telopeptides (CTX) Cystatin C Supplemental tests to help differentiate a diagnosis of ALZHEIMER DISEASE from other forms of dementia: * Amyloid β42 (Aβ42) and Tau protein Crosslinked C−telopeptides (CTX) Fibronectin Troponin As a cardiac biomarker, this protein has been used in conjunction with troponin to help diagnose or rule out a heart attack: * Brain natriuretic peptide (BNP) Cross−linked C−telopeptides (CTX) Cystatin C Myoglobin Gold standard= in the diagnosis of acute coronary syndrome (ACS): * Brain natriuretic peptide (BNP) Cross−linked c−telopeptides Myoglobin Troponin Ratio: ACUTE CORONARY SYNDROME/MYOCARDIAL INFARCTION Cardiac troponin (cTn) represents a complex of regulatory proteins that include troponin I (cTnI) and troponin T (cTnT) that are specific to heart muscle. cTnI and cTnT are the gold standard= in the diagnosis of acute coronary syndrome (ACS). cTn should be measured in all patients presenting with symptoms suggestive of ACS, in conjunction with physical examination and ECG. Which test, if elevated, would PROVIDE INFORMATION about risk for developing coronary artery disease? * CK−MB hs−CRP Myoglobin Troponin Ratio: HIGH−SENSITIVITY CRP Considered a GOOD PREDICTOR TEST for assessing cardiovascular risk If elevated, which laboratory test would support a diagnosis of CONGESTIVE HEART FAILURE? * Albumin cobalt binding B−type natriuretic peptide Homocysteine Troponin Ratio: B-type (brain) natriuretic peptide (BNP) is used to determine if physical symptoms are related to congestive heart failure. Which two tests detect swelling of the ventricles that occurs in congestive heart failure? * BNP and electrocardiogram BNP and echocardiogram Troponin T and electrocardiogram Troponin I and echocardiogram Which of the following laboratory tests is a marker for ISCHEMIC HEART DISEASE? * Albumin cobalt binding CK−MB isoforms Free fatty acid binding protein Myosin light chain In a person with normal glucose metabolism, the blood glucose level usually increases rapidly after carbohydrates are ingested but returns to a normal level after: * 30 minutes 45 minutes 60 minutes (1 hour) 120 minutes (2 hours) Glucose measurements can be mg/dL erroneously higher by reducing methods than by more accurate enzymatic methods. * 1 to 5 mg/dL 5 to 15 mg/dL 20 to 25 mg/dL 30 to 35 mg/dL Ratio: Glucose measurements can be 5 to 15 mg/dL erroneously higher by reducing methods than by more accurate enzymatic methods. Select the enzyme that is most specific for beta D− glucose: * Glucose oxidase Glucose−6−phosphate dehydrogenase Hexokinase Phosphohexose isomerase Ratio: Glucose oxidase is the most specific enzyme reacting with only beta D-glucose. Glucose oxidase converts beta D-glucose to gluconic acid. Mutarotase may be added to the reaction to facilitate the conversion of alpha-D-glucose to beta-D-glucose. Select the coupling enzyme used in the hexokinase method for glucose: * Glucose dehydrogenase Glucose−6−phosphatase Glucose−6−phosphate dehydrogenase Peroxidase Ratio: The hexokinase method is considered more accurate than the glucose oxidase methods because the coupling reaction using glucose-6-phosphate dehydrogenase is highly specific; therefore, it has less interference than the coupled glucose oxidase procedure. Which of the following is a potential source of error in the HEXOKINASE METHOD? * Galactosemia Hemolysis Sample collected in fluoride Ascorbic acid Gross hemolysis and extremely elevated bilirubin may cause in HEXOKINASE RESULTS. * False increase False decrease No effect Variable VERY LOW OR UNDETECTABLE C−peptide: * A 62−year−old patient presents to the physician with report of increased thirst and increased urination, particularly at night. The physician requests a series of tests over the next few days. The following data are received: RANDOM GLUCOSE: 186 mg/dL; FASTING GLUCOSE: 114 mg/dL; 2−HOUR OGTT: 153 mg/dL HbA1c: 5.9%. Which of the following conclusions may be made regarding these data? * Data represents normal glucose status Data represents an impaired glucose status Data represents the presence of insulinoma Data represents diagnosis of diabetes Ratio: Resting plasma glucose NORMAL 140 IMPAIRED 140 – 199 DIAGNOSTIC ≥ 200 mg/dL Fasting plasma glucose NORMAL 100 IMPAIRED 100 – 125 DIAGNOSTIC ≥ 126 mg/dL 2-hour OGTT NORMAL 140 IMPAIRED 140 – 199 DIAGNOSTIC ≥ 200 mg/dL HbA1c NORMAL 5.7 % IMPAIRED 5.7 – 6.4% DIAGNOSTIC ≥ 6.5% What is the recommended cutoff value for adequate control of blood glucose in diabetics as measured by glycated hemoglobin? * 5% 6.5% 9.5% 11% Type 1 diabetes mellitus Type 2 diabetes mellitus A factor, other than average plasma glucose values, that can affect the HbA1c level is: * Serum ketone bodies Red blood cell life span Ascorbic acid intake Increased triglyceride levels Ratio: Two factors determine the glycosylated hemoglobin levels: the average glucose concentration and the red blood cell life span. If the red blood cell life span is decreased because of another disease state such as hemoglobinopathies, the hemoglobin will have less time to become glycosylated and the glycosylated hemoglobin level will be lower. LONG−TERM estimation of glucose concentration can be followed by measuring: * Glycosylated hemoglobin (HbA1c) Fructosamine Ratio: Long-term estimation of glucose concentration can be followed by measuring glycosylated hemoglobin (Hb A1c). A level of 8% or less is considered good= glycemic control. Because the average red blood cell lives approximately 120 days, the glycosylated hemoglobin level at any one time reflects the average blood glucose level over the previous 2 to 3 months. Therefore, measuring the glycosylated hemoglobin provides the clinician with a time-averaged picture of the patient’s blood glucose concentration over the past 3 months. Most widely used to assess SHORT−TERM (3 to 6 weeks) glycemic control: * Glycosylated hemoglobin (HbA1c) Fructosamine Ratio: FRUCTOSAMINE: GLYCOSYLATED ALBUMIN Formation of glucose−6−phosphate from noncarbohydrate sources: * Glycolysis Gluconeogenesis Glycogenolysis Glycogenesis Ratio: Glycolysis Metabolism of glucose molecule to pyruvate or lactate for production of energy Gluconeogenesis Formation of glucose-6-phosphate from noncarbohydrate sources Glycogenolysis Breakdown of glycogen to glucose for use as energy Glycogenesis Conversion of glucose to glycogen for storage Lipogenesis Conversion of carbohydrates to fatty acids Lipolysis Decomposition of fat HYPERGLYCEMIC FACTOR produced by the pancreas is: Epinephrine Glucagon Growth hormone Insulin Ratio: Glucagon is the primary hormone responsible for increasing glucose levels. It is synthesized by the ALPHA-cells of islets of Langerhans in the pancreas and released during stress and fasting states. ACTION OF GLUCAGON Increases glycogenolysis: glycogen → glucose Increases gluconeogenesis: fatty acids → acetyl-CoA → ketone, proteins → amino acids Fructosamine assays are the most widely used to assess short-term (3 to 6 weeks) glycemic control because the average half-life of the proteins is 2–3 weeks. HYPOGLYCEMIC FACTOR produced by the pancreas is: * Epinephrine Glucagon Growth hormone Insulin Ratio: Insulin is the only hormone that decreases glucose levels and can be referred to as a hypoglycemic agent. Insulin is the primary hormone responsible for the entry of glucose into the cell. It is synthesized by the beta cells of islets of Langerhans in the pancreas. Usual dose of LACTOSE in the oral lactose tolerance test is: 25 grams 50 grams 75 grams 100 grams Ratio: ORAL LACTOSE TOLERANCE TESTS, measuring the increase in plasma glucose or galactose following ingestion of lactose, have been used to diagnose lactase deficiency. It decreases plasma glucose levels by increasing the transport entry of glucose in muscle and adipose tissue by way of nonspecific receptors. It also regulates glucose by increasing glycogenesis, lipogenesis, and glycolysis and inhibiting glycogenolysis. ACTION OF INSULIN Increases glycogenesis and glycolysis: glucose → glycogen → pyruvate → acetyl-CoA Increases lipogenesis Decreases glycogenolysis What would an individual with CUSHING SYNDROME tend to exhibit? * Hyperglycemia Hypoglycemia Normal blood glucose level Decreased 2−hour postprandial glucose Ratio: CORTISOL INCREASES BLOOD GLUCOSE. Symptoms of HYPOGLYCEMIA usually occur when blood glucose has fallen below mg/dL. * Below 50 mg/dL Below 60 mg/dL Below 70 mg/dL Below 80 mg/dL What is the compound that comprises the majority of the nonprotein−nitrogen fractions in serum? * Uric acid Creatinine Ammonia Urea Express 30 mg/dL of urea nitrogen as urea. * 14 mg/dL 20 mg/dL 50 mg/dL 64 mg/dL Ratio: UREA AMINO ACIDS URIC ACID CREATININE CREATINE AMMONIA Constituents in the plasma that contain the element nitrogen are categorized as being protein- or nonprotein-nitrogen compounds. The principal substances included among the nonprotein-nitrogen compounds are urea, amino acids, uric acid, creatinine, creatine, and ammonia. Of these compounds, urea is present in the plasma in the greatest concentration, comprising approximately 45% of the nonprotein-nitrogen fraction. Urea is produced from: * Catabolism of proteins and amino acids Oxidation of purines Oxidation of pyrimidines Breakdown of complex carbohydrates In the urea method, the enzymatic action of urease is inhibited when blood for analysis is drawn in a tube containing what anticoagulant? * Sodium heparin Sodium fluoride Sodium oxalate EDTA Urea concentration is calculated from the BUN by multiplying by a factor of: * 0.5 2.14 6.45 14 In the diacetyl method, what does diacetyl react with to form a yellow product? * Ammonia Urea Uric acid Nitrogen It is the result of POOR PERFUSION of the kidneys and therefore diminished glomerular filtration. The kidneys are otherwise normal in their functioning capabilities. Poor perfusion can result from dehydration, shock, diminished blood volume, or congestive heart failure. * Pre−renal azotemia Renal azotemia Post−renal azotemia Ratio: UREMIA: abnormally high urea nitrogen in the blood AZOTEMIA: significant increase in the plasma concentrations of UREA and CREATININE In the Berthelot reaction, what contaminant will cause the urea level to be falsely elevated? * Sodium fluoride Protein Ammonia Bacteria Ratio: The Berthelot reaction is based on the production of a blue-indophenol compound when ammonia reacts in an alkaline medium with phenol and sodium hypochlorite. This basic colorimetric reaction can be used to quantify both urea and blood ammonia levels. PRE-RENAL AZOTEMIA * Result of poor perfusion of the kidneys and therefore diminished glomerular filtration; kidneys are otherwise normal in their functioning capabilities * Poor perfusion can result from dehydration, shock, diminished blood volume, or congestive heart failure. Another cause of prerenal azotemia is increased protein breakdown, as in fever, stress, or severe burns RENAL AZOTEMIA * Caused primarily by diminished glomerular filtration as a consequence of acute or chronic renal disease * Such diseases include acute glomerulonephritis, chronic glomerulonephritis, polycystic kidney disease, and nephrosclerosis. Therefore, any ammonia contamination (i.e., in the distilled water used to make reagents for the urea procedure and on glassware) must be avoided so that falsely elevated urea values will not be obtained. Blood ammonia levels are usually measured in order to evaluate: * Renal failure Acid−base status Hepatic coma Gastrointestinal malabsorption POST-RENAL AZOTEMIA * Usually the result of any type of obstruction in which urea is reabsorbed into the circulation * Obstruction can be caused by stones, an enlarged prostate gland, or tumors. It is caused primarily by DIMINISHED GLOMERULAR FILTRATION as a consequence of acute or chronic renal disease. Such diseases include acute glomerulonephritis, chronic glomerulonephritis, polycystic kidney disease, and nephrosclerosis. * Pre−renal azotemia Renal azotemia Post−renal azotemia Which of the following disorders is NOT associated with an elevated blood ammonia level? * Reye syndrome Renal failure Chronic liver failure Diabetes mellitus When measuring ammonia blood levels, which of the following might cause a false increase in this analyte? * The patient had two cigarettes 15 minutes prior to blood draw. The patient was fasting for hours prior to blood collection. Immediately after phlebotomy, the blood sample was maintained on ice. The patient had a steak dinner the night before the blood draw. None of the above will falsely increase the blood ammonia levels. The assay for urea is only a rough estimate of renal function and will not show any significant level of increased concentration until the glomerular filtration rate is decreased by at least . * Glomerular filtration rate is decreased by at least 50% Glomerular filtration rate is decreased by at least 60% Glomerular filtration rate is decreased by at least 70% Glomerular filtration rate is decreased by at least 80% An increased serum level of which of the following analytes is most commonly associated with decreased glomerular filtration? * Creatinine Uric acid Urea Ammonia Ratio: An increase in the serum creatinine level would be indicative of decreased glomerular filtration. Although uric acid, urea, and ammonia levels may be increased with decreased glomerular filtration, increased levels of these analytes are associated with a number of specific metabolic diseases and, therefore, they are not used as indicators of the glomerular filtration rate. What analyte is measured using the Jaffe reaction? * Urea Uric acid Ammonia Creatinine The most widely used test of overall renal function is: * Urea Creatinine Proteinuria Cystatin C What is the normal BUN/CREATININE RATIO? * 1:5 to 1:10 1:10 to 1:20 5:1 to 10:1 10:1 to 20:1 What compound normally found in urine may be used to assess the completeness of a 24−hour urine collection? * Urea Uric acid Creatine Creatinine What is the end product of purine catabolism in humans? * Urea Uric acid Allantoin Ammonia When mixed with phosphotungstic acid, what compound causes the reduction of the former to a tungsten blue complex? * Which analyte should be reported as a ratio using creatinine concentration as a reference? * Urinary microalbumin Urinary estriol Urinary sodium Urinary urea Urea Ammonia Creatinine Uric acid Which of the following disorders is best characterized by laboratory findings that include increased serum levels of inorganic phosphorus, magnesium, potassium, uric acid, urea, and creatinine and decreased serum calcium and erythropoietin levels? * An ENDOGENOUS substance assayed to assess the glomerular filtration rate maybe described as being filtered by the glomeruli, not reabsorbed by the tubules, and only secreted by the tubules when plasma levels become elevated. What is this frequently assayed substance? * Creatinine Chronic renal failure Renal tubular disease Nephrotic syndrome Acute glomerulonephritis In gout, what analyte deposits in joints and other body tissues? * Calcium Creatinine Urea Uric acid The turbid, or milky, appearance of serum after fat ingestion is termed postprandial lipemia, which is caused by the presence of what substance? * Bilirubin Cholesterol Chylomicron Phospholipid When the plasma appears OPAQUE AND MILKY, the triglyceride level is probably: * A complete deficiency of hypoxanthine guanine phosphoribosyl transferase results in which disease? * Lesch−Nyhan syndrome Maple syrup urine disease Reye’s syndrome Megaloblastic anemia During chemotherapy for leukemia, which of the following analytes would most likely be elevated in the blood? * Uric acid Urea Creatinine Ammonia Ratio: An increase in serum uric acid levels may be seen during chemotherapy for leukemia. The cause of this is the accelerated breakdown of cell nuclei in response to the chemotherapy. Other proliferative disorders that may respond similarly are lymphoma, multiple myeloma, and polycythemia. It is important that serum uric acid be monitored during chemotherapy to avoid nephrotoxicity. Less than 100 mg/dL Less than 200 mg/dL Greater than 300 mg/dL Greater than 600 mg/dL Ratio: The appearance of the plasma or serum can be observed and noted after a minimum 12-hour fast. If the plasma is clear, the triglyceride level is probably less than 200 mg/dL. When the plasma appears hazy or turbid, the triglyceride level has increased to greater than 300 mg/dL, and if the specimen appears opaque and milky (lipemic, from chylomicrons), the triglyceride level is probably greater than 600 mg/dL. Note: 1. Clear plasma: TAG 200 mg/dL 2. Hazy or turbid plasma: TAG 300 mg/dL 3. Opaque or milky plasma: TAG 600 mg/dL Which of the following tests would most likely be included in a routine lipid profile? * Total cholesterol, triglyceride, fatty acid, chylomicron Total cholesterol, triglyceride, HDL cholesterol, phospholipid Triglyceride, HDL cholesterol, LDL cholesterol, chylomicron Total cholesterol, triglyceride, HDL cholesterol, LDL cholesterol To produce reliable results, when should blood specimens for lipid studies be drawn? * In the fasting state, approximately 12 hours after eating Which of the following lipid tests is LEAST affected by the fasting status of the patient? * Cholesterol Triglyceride Fatty acid Lipoprotein The kinetic methods for quantifying serum triglyceride employ enzymatic hydrolysis. The hydrolysis of triglyceride may be accomplished by what enzyme? * Amylase Leucine aminopeptidase Lactate dehydrogenase Lipase The largest and the least dense of the lipoprotein particles: * LDL HDL VLDL Chylomicrons Ratio: Chylomicrons, which contain apo B-48, are the largest and the least dense of the lipoprotein particles. HDL, the smallest and most dense lipoprotein particle, is synthesized by both the liver and the intestine. The smallest and most dense lipoprotein particle: * LDL HDL VLDL Chylomicrons An abnormal lipoprotein present in patients with biliary cirrhosis or cholestasis: * LDL B−VLDL Lp(a) LpX Exogenous triglycerides are transported in the plasma in what form? * Phospholipids Cholestryl esters Chylomicrons Free fatty acids Select the lipoprotein fraction that carries most of the endogenous triglycerides. * VLDL HDL LDL Chylomicrons Each lipoprotein fraction is composed of varying amounts of lipid and protein components. The beta− lipoprotein fraction consists primarily of which lipid? * Fatty acid Cholesterol Phospholipid Triglyceride High levels of cholesterol leading to increased risk of coronary artery disease would be associated with which lipoprotein fraction? * LDL VLDL HDL Chylomicrons What is the sedimentation nomenclature associated with alpha−lipoprotein? * Very−low−density lipoproteins (VLDLs) High−density lipoproteins (HDLs) Low−density lipoproteins (LDLs) Chylomicrons Ratio: The beta-lipoprotein fraction is composed of approximately 50% cholesterol, 6% triglycerides, 22% phospholipids, and 22% protein. The beta-lipoproteins, which are also known as the low-density lipoproteins (LDLs), are the principal transport vehicle for cholesterol in the plasma. The protein composition of HDL is what percentage by weight? * Less than 2% 25% 50% 90% The quantification of the high−density lipoprotein cholesterol level is thought to be significant in the risk assessment of what disease? * Pancreatitis Cirrhosis Coronary artery disease Hyperlipidemia Coronary heart disease POSITIVE risk factor: * HDL−C concentration 40 mg/dL None of these Ratio : POSITIVE (INCREASED) RISK FACTORS  Age: g 45 y for men; g 55 y or premature menopause for women  Family history of premature CHD  Current cigarette smoking  Hypertension (blood pressure g 140/90 mm Hg or taking antihypertensive medication)  LDL-C concentration g 160 mg/dL (g 4.1 mmol/L), with f 1 risk factor  LDL-C concentration g 130 mg/dL (3.4 mmol/L), with g 2 risk factors  LDL-C concentration g 100 mg/dL (2.6 mmol/L), with CH D or risk equivalent  HDL-C concentration 40 mg/dL ( 1.0 mmol/L)  Diabetes mellitus = CH D risk equivalent  Metabolic syndrome (multiple metabolic risk factors) NEGATIVE (DECREASED) RISK FACTORS  HDL-C concentration g 60 mg/dL (g 1.6 mmol/L)  LDL-C concentration 100 mg/dL ( 2.6 mmol/L) Which apoprotein is inversely related to risk of coronary heart disease? * Apoprotein A−I Apoprotein B100 Apoprotein C−II Apoprotein E4 LDL primarily contains: * Apo AI Apo−AII Apo−B100 Apo−B48 Ratio: LDL primarily contains apo B-100 and is more cholesterol rich than other apo B–containing lipoproteins. Note: Apo-AI, Apo-AII = HDL Apo-B100 = LDL, VLDL Apo-B48 = chylomicrons The VLDL fraction primarily transports what substance? Cholesterol Chylomicron Triglyceride Phospholipid A commonly used precipitating reagent to separate HDL cholesterol from other lipoprotein cholesterol fractions: Zinc sulfate Trichloroacetic acid Heparin−manganese Isopropanol Which of the following is associated with Tangier disease? * Apoprotein C−II deficiency Homozygous apo−B100 deficiency Apoprotein C−II activated lipase Apoprotein A−I deficiency A patient's total cholesterol is 300 mg/dL, his HDL cholesterol is 50 mg/dL, and his triglyceride is 200 mg/dL. What is this patient's calculated LDL cholesterol? 200 210 290 350 Ratio: Once the total cholesterol, triglyceride, and HDL cholesterol are known, LDL cholesterol can be quantified by using the Friedewald equation LDL cholesterol = Total cholesterol 4 (HDL cholesterol + Triglyceride/5) In this example, all results are in mg/dL: LDL cholesterol = 300 - (50 + 200/5) = 300 - (90) = 210 mg/dL The Friedewald formula is not valid for triglycerides over . * Triglycerides over 100 mg/dL Triglycerides over 200 mg/dL Triglycerides over 300 mg/dL Triglycerides over 400 mg/dL Select the order of mobility of lipoproteins electrophoresed on cellulose acetate or agarose at pH 8.6. * – Chylomicrons→pre−β →´→³+ – β→pre−β→³→chylomicrons + – Chylomicrons →´→pre−β→³ + – α→´→pre−β→chylomicrons + Ratio: Although pre-β lipoprotein is lower in density than β lipoprotein, it migrates faster on agarose or cellulose acetate owing to its more negative apoprotein composition. LIPOPROTEINS 1. By electrophoresis From the origin: chylomicrons beta (LDL) prebeta (VLDL) alpha (HDL) Anode --------- 2. By ultracentrifugation From the least dense and largest: chylomicrons VLDL LDL HDL most dense and smallest Floating beta lipoprotein: * Lp(a) B−VLDL Sinking pre−β−lipoprotein: * Lp(a) B−VLDL Which of the following may be described as a variant form of LDL, associated with increased risk of atherosclerotic cardiovascular disease? * Lp(a) HDL Apo−AI Apo−AII Type V hyperlipoproteinemia: * Extremely elevated TG due to the presence of chylomicrons Elevated LDL and VLDL Elevated VLDL Elevated VLDL and presence of chylomicrons A 46−year−old known alcoholic with liver damage is brought into the emergency department unconscious. In what way would you expect his plasma lipid values to be affected? * Increased total cholesterol, triglyceride, LDL, and VLDL Increased total cholesterol and triglyceride, decreased LDL and VLDL Decreased total cholesterol, triglyceride, LDL, and VLDL Normal lipid metabolism, unaffected by the alcoholism Ratio: If the alcoholism has advanced to the state where there is liver damage, the liver can become inefficient in its metabolism of fats, leading to an increase of total cholesterol, triglyceride, LDL, and/or VLDL in the bloodstream. The elevation of these lipids along with the previous liver damage (e.g., cirrhosis) leads to a poor prognosis for the patient. What is the IMMEDIATE PRECURSOR of bilirubin formation? * Which of the following functions as a transport protein for bilirubin in the blood? * Biliverdin Albumin To quantify serum bilirubin levels, it is necessary that bilirubin couples with diazotized sulfanilic acid to form what complex? * What term is used to describe the accumulation of bilirubin in the skin? * Jaundice Azobilirubin In the condition kernicterus, the abnormal accumulation of bilirubin occurs in what tissue? * What enzyme catalyzes the conjugation of bilirubin? * Brain Uridine diphosphate glucuronyltransferase (UDPGT) As a reduction product of bilirubin catabolism, this compound is partially reabsorbed from the intestine through the portal circulation for reexcretion by the liver. What is this compound? * What breakdown product of bilirubin metabolism is produced in the colon from the oxidation of urobilinogen by microorganisms? * Urobilinogen Urobilin Which of the following factors will NOT adversely affect the accurate quantification of bilirubin in serum? * Which of the following does NOT accurately describe direct bilirubin? Specimen refrigeration Insoluble in water Ratio: Bilirubin will deteriorate when exposed to either white or UV light. This deterioration is also temperature sensitive. Thus, specimens for bilirubin analysis should be stored in the dark at refrigerator temperature until the assay can be performed. Lipemia should be avoided, due to its interference with spectrophotometric analyses. Because hemoglobin reacts with diazo reagent, use of hemolyzed specimens should be avoided. Hemolysis will cause bilirubin results to be falsely low. Which bilirubin fraction is unconjugated and covalently bound to albumin? * Alpha Beta Delta Gamma Ratio: Four bilirubin fractions represented by Greek letters have been identified: unconjugated (alpha), monoconjugated (beta), diconjugated (gamma), and unconjugated bilirubin covalently bound to albumin (delta). Delta-bilirubin is normally present in low concentration in the blood, and it is known to react directly with diazotized sulfanilic acid. Increased serum levels of delta-bilirubin are associated with liver-biliary disease. As the red blood cells disintegrate, hemoglobin is released and converted to the pigment bilirubin. Which organ is primarily responsible for this function? * Spleen Ratio: The cells of the reticuloendothelial system are responsible for the removal of old red blood cells from the peripheral circulation. As the red blood cells reach the end of their 120-day life span, the specialized cells mainly of the spleen phagocytize the aged cells and convert the released hemoglobin into the excretory pigment bilirubin. Excreted in the urine of jaundiced patients: * Conjugated bilirubin Which of the following reagent systems contains the components sulfanilic acid, hydrochloric acid, and sodium nitrite? * Diazo Indirect−reacting bilirubin may be quantified by reacting it initially in which reagent? * Dilute hydrochloric acid Dilute sulfuric acid Caffeine−sodium benzoate Sodium hydroxide Ratio: Unlike direct bilirubin, indirect-reacting bilirubin is insoluble in deionized water and dilute hydrochloric acid. Indirect-reacting bilirubin must first be mixed with methanol or caffeine-sodium benzoate to solubilize it before proceeding with the diazo reaction. Note: EVELYN-MALLOY: methanol JENDRASSIK-GROF: caffeine-sodium benzoate What condition is characterized by an elevation of total bilirubin primarily due to an increase in the CONJUGATED BILIRUBIN fraction? * Which of the following disorders is characterized by an INABILITY TO TRANSPORT BILIRUBIN from the sinusoidal membrane into the hepatocyte? * Obstructive jaundice Gilbert syndrome Ratio: Gilbert syndrome is a preconjugation transport disturbance. In this disorder the hepatic uptake of bilirubin is defective because the transportation of bilirubin from the sinusoidal membrane to the microsomal region is impaired. Which of the following is characteristic of hemolytic jaundice? * Unconjugated serum bilirubin level increased What may be the cause of NEONATAL PHYSIOLOGICAL JAUNDICE? * Deficiency in the bilirubin conjugation enzyme system Ratio: The enzyme uridine diphosphate glucuronyltransferase catalyzes the conjugation of bilirubin with glucuronic acid. In newborns, especially premature infants, this liver enzyme system is not fully developed or functional. Because of this deficiency in the enzyme system, the concentration of unconjugated bilirubin rises in the blood, because only the conjugated form may be excreted through the bile and urine. The increased levels of unconjugated bilirubin will cause the infant to appear jaundiced. Generally, this condition persists for only a short period because the enzyme system usually becomes functional within several days after birth. Which of the following characterizes Crigler−Najjar syndrome? * Deficiency of the enzyme system required for conjugation of bilirubin Ratio: Both Crigler-Najjar syndrome and neonatal jaundice, a physiological disorder, are due to a deficiency in the enzyme-conjugating system. With a deficiency in uridine diphosphate glucuronyltransferase, the liver is unable to conjugate bilirubin, and both of these conditions are characterized by increased levels of unconjugated bilirubin. Unlike Crigler-Najjar syndrome, which is a hereditary disorder, neonatal physiological jaundice is a temporary situation that usually corrects itself within a few days after birth. Which of the following is NOT characteristic of Dubin− Johnson syndrome? * Impaired excretion of bilirubin into the bile Hepatic uptake of bilirubin is normal Inability to conjugate bilirubin Increased level of bilirubin in urine Beta−gamma bridging effect: * Multiple myeloma Hepatic cirrhosis Nephrotic syndrome Inflammation Ratio: Gamma spike: multiple myeloma Beta-gamma bridging: hepatic cirrhosis α1 globulin flat curve: juvenile cirrhosis (AATdeficiency) Α2 globulin band spike: nephrotic syndrome Spikes in α1, α2 and β: inflammation Less than 80% liver damage: * Hepatitis The anticoagulant of choice for arterial blood gas measurements is in the state. * Lithium heparin; dry If a blood gas specimen is left exposed to air, which of the following changes will occur? * pO2 and pH increase; pCO2 decreases Ratio: HEPATITIS: less than 80% liver damage High: AST, ALT, LD, ALP, bilirubin Normal: Total protein, albumin, ammonia 80% liver tissue damage: * Cirrhosis How would blood gas parameters change if a sealed specimen is left at room temperature for 2 or more hours? * pO2 decreases, pCO2 increases, pH decreases Destruction of liver architecture: * Cirrhosis Increased in hepatic jaundice: * B1 and B2 Which is the most predominant buffer system in the body? * Bicarbonate/carbonic acid Ratio: Hemolytic jaundice: unconjugated bilirubin (B1) Hepatic jaundice: unconjugated and conjugated bilirubin (B1 and B2) Obstructive jaundice: conjugated bilirubin (B2) To maintain a pH of 7.4 in plasma, it is necessary to maintain a: * 20:1 ratio of bicarbonate to carbonic acid Which set of results is consistent with uncompensated respiratory alkalosis? * pH 7.66 HCO3− 22 mmol/L pCO2 20 mm Hg The normal ratio of CARBONIC ACID TO BICARBONATE in arterial blood is: * 1:20 Driving force of the bicarbonate buffer system: * Carbon dioxide Fever: * Fever will decrease pO2 by 7% Fever will increase pCO2 by 3% The role of the lungs and kidneys in maintaining pH is depicted with the Henderson−Hasselbalch equation. The numerator (HCO3−) denotes kidney functions, and the denominator (pCO2) denotes lung function. In the plasma, an excess in the concentration of bicarbonate without a change in pCO2 from normal will result in what physiological state? * Metabolic alkalosis Ratio: TIPS FOR EVALUATING ACID-BASE DISORDERS 1. Look at the pH: determine if acidosis or alkalosis 2. Compare pCO2 and HCO3- A. pCO2 going opposite to pH – RESPIRATORY Abnormal pCO2 respiratory [↓pH ↑pCO2 respiratory acidosis] [↑pH ↓pCO2 respiratory alkalosis] B. HCO3- going same direction as pH - METABOLIC Abnormal HCO3- metabolic [↓pH ↓HCO3- metabolic acidosis] [↑ pH ↑ HCO3- metabolic alkalosis] 3. If pH is normal, full compensation occurred 4. If main compensatory mechanism kicked in, but pH still out of normal range, partial compensation has occurred Which set of results is consistent with uncompensated metabolic acidosis? * pH 7.25 HCO3− 15 mmol/L pCO2 37 mm Hg A patient’s blood gas results are: pH = 7.50; pCO2 = 55 mm Hg; and HCO3– = 40 mmol/L. These results indicate: Metabolic alkalosis The following conditions are all causes of alkalosis. Which condition is associated with respiratory alkalosis? Anxiety Which of the following blood gas parameters are measured directly by the blood gas analyzer electrochemically as opposed to being calculated by the instrument? * pH, pCO2 and pO2 The properties of enzymes are correctly described by which of the following statements? * Enzymes are protein catalysts of biological origin. Ratio: pH, pCO2, and pO2 are measured directly from the specimen by utilizing electrodes. The pH and PCO2 electrodes are potentiometric where the voltage produced across a semipermeable membrane to hydrogen ions or CO2 gas is proportional to the "activity" of those ions in the patient's sample. Activity is measured in voltage whose value can be presented in terms of concentration. pO2 is measured similarly, but using an amperometric electrode. Note: pH and pCO2 = POTENTIOMETRY pO2 = AMPEROMETRY What does an increase in the serum enzyme levels indicate? * Tissue damage and necrosis Ratio: The majority of serum enzymes that are of interest clinically are of intracellular origin. These enzymes function intracellularly, with only small amounts found in serum as a result of normal cellular turnover. Increased serum levels are due to tissue damage and necrosis, where the cells disintegrate and leak their contents into the blood. Thus, elevated serum levels of intracellular enzymes are used diagnostically to assess tissue damage. When measuring enzyme activity, if the instrument is operating 5˚C lower than the temperature prescribed for the method, how will the results be affected? * Lower than expected The shape of the key (substrate) must fit into the lock (enzyme): * Lock−and−key theory by Emil Fischer Ratio: LOCK-AND-KEY (EMIL FISCHER) The shape of the key (substrate) must fit into the lock (enzyme) INDUCED-FIT (DANIEL KOSHLAND) Substrate binding to the active site of the enzyme The reaction rate is directly proportional to substrate concentration: * First−order kinetics The reaction rate depends only on enzyme concentration: * Zero−order kinetics Ratio: Factors that affect enzyme assays include temperature, pH, substrate concentration, and time of incubation. For each clinically important enzyme, the optimum temperature and pH for its specific reaction are known. When lower than optimum temperature or pH is employed, the measured enzyme activity will be lower than the expected activity value. As