Quiz 3: Cholesterol Testing Methods

Question 1

Elevated Cholesterol

Answer 1

Atherosclerosis, coronary artery disease, increased risk of heart attack

Question 2

Decreased Cholesterol

Answer 2

Liver Disease

Question 3

Enzymatic Testing Methodologies

Answer 3

Cholesterol ester + water and cholesterol esterase gives cholesterol + fatty acid
Cholesterol + O2 and cholesterol oxidase gives cholestenone H2O2
H2O2 + phenol + 4-aminoantipyrine and peroxidase gives quinoneimine dye and water

Question 4

HDL Cholesterol Testing

Answer 4

Increased levels are assoc. with decreased risk of coronary artery disease, decreased levels indicate the opposite
Testing:
- Precipitate LDL/VLDL: with (dextran or heparin) sulfate-magnesium chloride, then assay the supernatant.
- Homogeneous assay: uses Ab to bind LDL and VLDL, enzymatic analysis can follow

Question 5

LDL Cholesterol Testing

Answer 5

Assoc. with artherosclerosis and coronary heart disease
Calculated or measured directly
- Friedewald formula (indirect):
+ LDL = total cholesterol - [HDL + triglyceride/5]
- Homogeneous assay: uses detergents to keep HDL/VLDL from binding with dye, then an enzymatic assay is preformed

Question 6

Triglyceride Testing Methodologies

Answer 6

Elevated levels assoc. with hyperlipoproteinemias, pancreatitis, alcoholism, obesity, hypothyroidism, nephrotic syndrome, and storage diseases
Triglyceride + water and lipase gives glycerol + fatty acids
Glycerol + ATP and glycerokinase gives glycerophosphate + ADP
Glycerophosphate + O2 and glycerophosphate oxidase gives dihydroxyacetone + H2O2
H2O2 + dye and peroxidase gives colored product and water