NCA Clinical Chemistry Exam
Study Guide
The turbid appearance of lipemic serum is due to an elevated level of
A. cholesterol
B. HDL
C. phospholipids
D. triglycerides - Answer D. triglycerides
A trough blood sample for routine therapeutic drug monitoring is usually obtained
A. just after a dose is administerd
B. just before the next scheduled dose
C. at the calculated peak time after a dose
D. one half-life after a dose is administerd - Answer B. just before the next scheduled
dose
To quantitate urinary vanillylmandelic acid (VMA), which of the following specimens
should be collected?
A. 24-hour urine collection
B. First morning urine sample
C. Ransom, mid-stream clean catch
D. 2-hour urine collection following the midday meal - Answer A. 24-hour urine collection
VMA is a metabolite of the catecholamines: epinephrine, norepinephrine, and dopamine.
Due to the potential effects of exercise, hydration, and body metabolism on excretion
rates, a 24-hour collection is the specimen of choice
Situation: It is 8:00 and you are working in the specimen receiving and processing area
of the lab. The following specimens are received. Which requires intervention before
proceeding with processing and testing?
A. Alkaline Phosphate/EDTA/0730
B. Glucose/sodium flouride/0610
,C. Blood Gases/ heparin, in ice slush/ 0735
D. Electrolytes (Na,K)/ lithium heparin/ 0550 - Answer A. Alkaline Phosphate/EDTA/0730
A single tube of CSF is received in the lab and the following tests requested: total
protein, albumin, IgG quantitaiton, microbial culture, gram stain, leukocyte count, and
differential cell count. The specimens should be sent to the various lab in which order?
A. Chem, heme, micro
B. Heme, chem, micro
C. Micro, heme, chem
D. Heme, micro, chem - Answer C. Micro, heme, chem
Which of the following components determines the wavelength of light that will pass
through the sample cuvette in a spectrophotometer?
A. Detector
B. Light source
C. Potentiometer
D. Monochromator - Answer D. Monochromator
Which of the following specimens usually requires concentration before analysis?
A. Urine for osmolality
B. Amniotic fluid for L/S ratio
C. Plasma for making a protein-free filtrate
D. CSF for protein electrophoresis - Answer D. CSF for protein electrophoresis
Protein content in CSF is usually low, so it must be concentrated 80-100 fold before
electrophoresis
You need to prepare a 1:4 filution of a serum specimen when using saline before
analysis. Which of the following pipetting steps would result in this dilution?
A. Pipet 0.5 mL serum, then add 1.0 mL saline
B. Pipet 1.0 mL serum, then add 2.0 mL saline
C. Pipet 1.5 mL serum, then add 4.5 mL saline
D. Pipet 2.0 mL serum, then add 5.0 mL saline - Answer C. Pipet 1.5 mL serum, then add
4.5 mL saline
,Which of the following situations indicates that an instrument problem is present and
requires further investigation?
A. A series of high anion gaps
B. A series of high glucose results
C. A series of low urine osmo results
D. A series of low urine SG results - Answer A. A series of high anion gaps
What part of a spectrophotometer determines the "b" in Beer's law A=abc?
A. Light
B. Monochromator
C. Cuvette
D. Detector - Answer C. Cuvette
A = abc is absorbance = (molar absorptivity)(light path)(analyte concentration)
Samples for calcium analysis by atomic absorption spectrophotometery should be
diluted with lanthanum solution because lanthanum ions
A. blank for variations in flame temperature
B. blank for variations in lamp intensity
C. emit light used as the internal standard
D. Enhance dissociation of calcium phosphate - Answer D. Enhance dissociation of
calcium phosphate
At a pH of 7.4, which of the enzymes listed catalyzes the following reaction? pyruvate +
NADH > lactate + NAD
A. lactate oxidase
B. Lactate dehydrogenase
C. Pyruvate Kinase
D. Pyruvate decarboxylase - Answer B. Lactate dehydrogenase
Chromatographic separation of a mixture of solutes is based on
A. variable solubilites of solutes in the mobile and stationary phase
B. spectral differences of solutes in the mobile and stationary phase
C. selective degradation of solutes by the mobile and stationary phases
, D. differential distribution of solutes between the mobile and stationary phases - Answer
D. differential distribution of solutes between the mobile and stationary phases
In a couples enzymatic method for measuring serum cholesterol, the color change
observed during the indicator reaction is dependent upon the generation of
A. ATP
B. NAD
C. Oxygen
D. hydrogen peroxide - Answer D. hydrogen peroxide
The enzymatic method for measuring total cholesterol incubates serum with cholesterol
esterase (to release free cholesterol). Subsequently, cholesterol oxidizes the
cholesterol producing hydrogen peroxide. In the presence of peroxidase, the hydrogen
peroxide produced oxidizes the reduced dye to form a colored product
pH 8.6 is used for serum protein electrophoresis so that:
A. all serum proteins will have a net negative charge
B. all serum proteins will have a net positive charge
C. electroendosmosis is avoided
D. heat production is minimized - Answer A. all serum proteins will have a net negative
charge
When quantitating serum protein using the biuret reaction, the biuret reagent is reacting
with
A. peptide bonds in proteins
B. tyrosine residues in proteins
C. free amino groups in proteins
D. ammonia released from proteins - Answer A. peptide bonds in proteins
Which one of the following protein fractions, when separted in serum by electrophoresis
on cellulose acetate, contains a single protein?
A. albumin
B. Alpha 1 - globulin
C. Alpha 2 - globulin
D. beta - globulin - Answer A. albumin
Study Guide
The turbid appearance of lipemic serum is due to an elevated level of
A. cholesterol
B. HDL
C. phospholipids
D. triglycerides - Answer D. triglycerides
A trough blood sample for routine therapeutic drug monitoring is usually obtained
A. just after a dose is administerd
B. just before the next scheduled dose
C. at the calculated peak time after a dose
D. one half-life after a dose is administerd - Answer B. just before the next scheduled
dose
To quantitate urinary vanillylmandelic acid (VMA), which of the following specimens
should be collected?
A. 24-hour urine collection
B. First morning urine sample
C. Ransom, mid-stream clean catch
D. 2-hour urine collection following the midday meal - Answer A. 24-hour urine collection
VMA is a metabolite of the catecholamines: epinephrine, norepinephrine, and dopamine.
Due to the potential effects of exercise, hydration, and body metabolism on excretion
rates, a 24-hour collection is the specimen of choice
Situation: It is 8:00 and you are working in the specimen receiving and processing area
of the lab. The following specimens are received. Which requires intervention before
proceeding with processing and testing?
A. Alkaline Phosphate/EDTA/0730
B. Glucose/sodium flouride/0610
,C. Blood Gases/ heparin, in ice slush/ 0735
D. Electrolytes (Na,K)/ lithium heparin/ 0550 - Answer A. Alkaline Phosphate/EDTA/0730
A single tube of CSF is received in the lab and the following tests requested: total
protein, albumin, IgG quantitaiton, microbial culture, gram stain, leukocyte count, and
differential cell count. The specimens should be sent to the various lab in which order?
A. Chem, heme, micro
B. Heme, chem, micro
C. Micro, heme, chem
D. Heme, micro, chem - Answer C. Micro, heme, chem
Which of the following components determines the wavelength of light that will pass
through the sample cuvette in a spectrophotometer?
A. Detector
B. Light source
C. Potentiometer
D. Monochromator - Answer D. Monochromator
Which of the following specimens usually requires concentration before analysis?
A. Urine for osmolality
B. Amniotic fluid for L/S ratio
C. Plasma for making a protein-free filtrate
D. CSF for protein electrophoresis - Answer D. CSF for protein electrophoresis
Protein content in CSF is usually low, so it must be concentrated 80-100 fold before
electrophoresis
You need to prepare a 1:4 filution of a serum specimen when using saline before
analysis. Which of the following pipetting steps would result in this dilution?
A. Pipet 0.5 mL serum, then add 1.0 mL saline
B. Pipet 1.0 mL serum, then add 2.0 mL saline
C. Pipet 1.5 mL serum, then add 4.5 mL saline
D. Pipet 2.0 mL serum, then add 5.0 mL saline - Answer C. Pipet 1.5 mL serum, then add
4.5 mL saline
,Which of the following situations indicates that an instrument problem is present and
requires further investigation?
A. A series of high anion gaps
B. A series of high glucose results
C. A series of low urine osmo results
D. A series of low urine SG results - Answer A. A series of high anion gaps
What part of a spectrophotometer determines the "b" in Beer's law A=abc?
A. Light
B. Monochromator
C. Cuvette
D. Detector - Answer C. Cuvette
A = abc is absorbance = (molar absorptivity)(light path)(analyte concentration)
Samples for calcium analysis by atomic absorption spectrophotometery should be
diluted with lanthanum solution because lanthanum ions
A. blank for variations in flame temperature
B. blank for variations in lamp intensity
C. emit light used as the internal standard
D. Enhance dissociation of calcium phosphate - Answer D. Enhance dissociation of
calcium phosphate
At a pH of 7.4, which of the enzymes listed catalyzes the following reaction? pyruvate +
NADH > lactate + NAD
A. lactate oxidase
B. Lactate dehydrogenase
C. Pyruvate Kinase
D. Pyruvate decarboxylase - Answer B. Lactate dehydrogenase
Chromatographic separation of a mixture of solutes is based on
A. variable solubilites of solutes in the mobile and stationary phase
B. spectral differences of solutes in the mobile and stationary phase
C. selective degradation of solutes by the mobile and stationary phases
, D. differential distribution of solutes between the mobile and stationary phases - Answer
D. differential distribution of solutes between the mobile and stationary phases
In a couples enzymatic method for measuring serum cholesterol, the color change
observed during the indicator reaction is dependent upon the generation of
A. ATP
B. NAD
C. Oxygen
D. hydrogen peroxide - Answer D. hydrogen peroxide
The enzymatic method for measuring total cholesterol incubates serum with cholesterol
esterase (to release free cholesterol). Subsequently, cholesterol oxidizes the
cholesterol producing hydrogen peroxide. In the presence of peroxidase, the hydrogen
peroxide produced oxidizes the reduced dye to form a colored product
pH 8.6 is used for serum protein electrophoresis so that:
A. all serum proteins will have a net negative charge
B. all serum proteins will have a net positive charge
C. electroendosmosis is avoided
D. heat production is minimized - Answer A. all serum proteins will have a net negative
charge
When quantitating serum protein using the biuret reaction, the biuret reagent is reacting
with
A. peptide bonds in proteins
B. tyrosine residues in proteins
C. free amino groups in proteins
D. ammonia released from proteins - Answer A. peptide bonds in proteins
Which one of the following protein fractions, when separted in serum by electrophoresis
on cellulose acetate, contains a single protein?
A. albumin
B. Alpha 1 - globulin
C. Alpha 2 - globulin
D. beta - globulin - Answer A. albumin
