BI525 Investigation of Disease
Testing and Automation
Testing and Automation II
Cellular Pathology
Dyes and Routine Staining Procedures
Immunocytochemistry
Immunochemical Techniques and Antibodies
Kidney Disease
Liver Function Tests
Fluid and Electrolyte Disorders
Calcium Distribution in the Body
Fluid and Electrolyte Disorders II
Fluid and Electrolyte Disorders III
IMDs and Newborn Screening
Abnormalities of Lipid Metabolism
Cancer
Clinical Enzymology and Biomarkers
Clinical Enzymology and Biomarkers II
Specific Protein Markers
Cancer Biochemistry and Tumour Markers
Tumour Markers II
Investigation of Endocrine Disease I
Investigation of Endocrine Disease II
,Testing and Automation
Three lab tests:
- Diagnostic
o Investigating the signs or symptoms of an illness shown by an individual.
- Screening
o Identifying of individuals in a population who are ‘at risk’ or
asymptomatic.
- Monitoring
o Check health status of person before procedure. Assessment after
diagnosis or treatment. Checking progress of chronic illness.
- Serum is blood plasma without clotting factors (i.e. thrombin, fibrinogen).
Factors affecting blood samples before analysis
- IV fluid contamination
o IV fluids are given to those who have imbalances in fluid and electrolyte
levels, this is done to restore the concentrations of deficient ions (i.e.
HCO3-, Ca2+).
o Collecting a blood sample above or below an IV lead to the contents
contaminating it, leading to a false result obtained after analysis. The IV
fluid can also dilute the blood sample, leading to reductions in the
analytes under study.
o Blood draws should be done on the other arm, but in cases where this
not possible, they should be taken above the IV after it has been turned
off for a minimum of 3 minutes.
o Chloride, potassium and glucose assays may be affected by IV fluid
contamination and so analyte values may be abnormally elevated or
increased.
- Age
o Most monitored analytes are age-related. Cholesterol levels in adults
may be higher than in a younger person. The enzyme alkaline
phosphatase (ALP) conc. may be higher in a child than in an older
person because their bones are still growing.
o ALP accumulation in the blood if the liver is inflamed or if any bile ducts
are blocked.
o Necessary to refer to conc. levels normal to the age of the patient.
- Venous stasis
o This is a reduction of blood flow through veins due to a tourniquet that is
too tight or has been left on too long, which can lead to false increases
or decreases in metabolic analytes.
o Constricting the arm causes a transfer of fluid from the blood to the
interstitial space. This may lead to increases in protein, cholesterol, iron,
K+ and lipids.
o Increases in certain ion levels may be due to excessive movement of the
arm.
o Venous stasis = increased pCO2 leading to a decrease in pH and HCO3-.
- Medication
o The use of drugs such as aspirin can increase the levels of
aminotransferase enzymes and ALP.
, o Can lead to erroneous analyte conc.
- Sample container
o Samples should be placed in the right containers as they have been
tested not to have any adverse effects on the contents.
o The types of analytical processes needed to be carried out on a blood
sample influences the order in which blood is put into vacutainers. This
is to prevent or reduce the cross-contamination of additives from the
different tubes, which can affect the analysis.
o E.g. EDTA chelates ions and so can elevate Na +/K+ ion levels and
reduce Ca2+/Fe2+ levels.
o Order of blood draw is also there to prevent contamination of blood from
bacteria on or in non-sterile tube stoppers.
Sample suitability (pre-analytical factors)
- Haemolysis
o Results in clinically significant changes in serum component
concentrations (I.e. ↑ K+, ↓ insulin, AST, Cl-, Na+).
o Affects spectrophotometric measurements; the greater the degree of
haemolysis, the redder the sample solution.
o Haemolysis is the rupture of RBCs and subsequent release of Hb. This
is shown in the serum.
o Burst RBCs can elevate iron levels.
▪ Hb has been shown to inhibit some enzymes.
▪ Intracellular fluid of the RBC can dilute the sample.
o Caused by mishandling of the sample (vigorous mixing).
- Lipaemia
o Excess lipids or fats in the blood.
o May be caused by an increase in the levels of chylomicrons in the blood
after a fatty meal.
o Affects colorimetry/
o Avoided by prolonged fasting (8 hours).
- Jaundice (icteric blood/icterus)
o A build-up of the orange bile pigment bilirubin due to liver damage or
excess haemolysis (haemolytic anaemia).
o Also affects colorimetric processes.
o Cannot be avoided as jaundice is a physiological condition caused by
disease.
Testing and Automation II
Electrochemical lab tests
- pH, ions, biosensors.
- pH meters work by measuring the potential difference of the solution the probe
is in. the hydrogen conc. can be calculated through the Nernst equation.
Testing and Automation
Testing and Automation II
Cellular Pathology
Dyes and Routine Staining Procedures
Immunocytochemistry
Immunochemical Techniques and Antibodies
Kidney Disease
Liver Function Tests
Fluid and Electrolyte Disorders
Calcium Distribution in the Body
Fluid and Electrolyte Disorders II
Fluid and Electrolyte Disorders III
IMDs and Newborn Screening
Abnormalities of Lipid Metabolism
Cancer
Clinical Enzymology and Biomarkers
Clinical Enzymology and Biomarkers II
Specific Protein Markers
Cancer Biochemistry and Tumour Markers
Tumour Markers II
Investigation of Endocrine Disease I
Investigation of Endocrine Disease II
,Testing and Automation
Three lab tests:
- Diagnostic
o Investigating the signs or symptoms of an illness shown by an individual.
- Screening
o Identifying of individuals in a population who are ‘at risk’ or
asymptomatic.
- Monitoring
o Check health status of person before procedure. Assessment after
diagnosis or treatment. Checking progress of chronic illness.
- Serum is blood plasma without clotting factors (i.e. thrombin, fibrinogen).
Factors affecting blood samples before analysis
- IV fluid contamination
o IV fluids are given to those who have imbalances in fluid and electrolyte
levels, this is done to restore the concentrations of deficient ions (i.e.
HCO3-, Ca2+).
o Collecting a blood sample above or below an IV lead to the contents
contaminating it, leading to a false result obtained after analysis. The IV
fluid can also dilute the blood sample, leading to reductions in the
analytes under study.
o Blood draws should be done on the other arm, but in cases where this
not possible, they should be taken above the IV after it has been turned
off for a minimum of 3 minutes.
o Chloride, potassium and glucose assays may be affected by IV fluid
contamination and so analyte values may be abnormally elevated or
increased.
- Age
o Most monitored analytes are age-related. Cholesterol levels in adults
may be higher than in a younger person. The enzyme alkaline
phosphatase (ALP) conc. may be higher in a child than in an older
person because their bones are still growing.
o ALP accumulation in the blood if the liver is inflamed or if any bile ducts
are blocked.
o Necessary to refer to conc. levels normal to the age of the patient.
- Venous stasis
o This is a reduction of blood flow through veins due to a tourniquet that is
too tight or has been left on too long, which can lead to false increases
or decreases in metabolic analytes.
o Constricting the arm causes a transfer of fluid from the blood to the
interstitial space. This may lead to increases in protein, cholesterol, iron,
K+ and lipids.
o Increases in certain ion levels may be due to excessive movement of the
arm.
o Venous stasis = increased pCO2 leading to a decrease in pH and HCO3-.
- Medication
o The use of drugs such as aspirin can increase the levels of
aminotransferase enzymes and ALP.
, o Can lead to erroneous analyte conc.
- Sample container
o Samples should be placed in the right containers as they have been
tested not to have any adverse effects on the contents.
o The types of analytical processes needed to be carried out on a blood
sample influences the order in which blood is put into vacutainers. This
is to prevent or reduce the cross-contamination of additives from the
different tubes, which can affect the analysis.
o E.g. EDTA chelates ions and so can elevate Na +/K+ ion levels and
reduce Ca2+/Fe2+ levels.
o Order of blood draw is also there to prevent contamination of blood from
bacteria on or in non-sterile tube stoppers.
Sample suitability (pre-analytical factors)
- Haemolysis
o Results in clinically significant changes in serum component
concentrations (I.e. ↑ K+, ↓ insulin, AST, Cl-, Na+).
o Affects spectrophotometric measurements; the greater the degree of
haemolysis, the redder the sample solution.
o Haemolysis is the rupture of RBCs and subsequent release of Hb. This
is shown in the serum.
o Burst RBCs can elevate iron levels.
▪ Hb has been shown to inhibit some enzymes.
▪ Intracellular fluid of the RBC can dilute the sample.
o Caused by mishandling of the sample (vigorous mixing).
- Lipaemia
o Excess lipids or fats in the blood.
o May be caused by an increase in the levels of chylomicrons in the blood
after a fatty meal.
o Affects colorimetry/
o Avoided by prolonged fasting (8 hours).
- Jaundice (icteric blood/icterus)
o A build-up of the orange bile pigment bilirubin due to liver damage or
excess haemolysis (haemolytic anaemia).
o Also affects colorimetric processes.
o Cannot be avoided as jaundice is a physiological condition caused by
disease.
Testing and Automation II
Electrochemical lab tests
- pH, ions, biosensors.
- pH meters work by measuring the potential difference of the solution the probe
is in. the hydrogen conc. can be calculated through the Nernst equation.
