CLS Lipid Panel Interpretation 2

Question 1

A patient's lipid panel shows LDL-C 160 mg/dL, HDL-C 38 mg/dL, TG 280 mg/dL, and total cholesterol 254 mg/dL. The Friedewald equation was used. Why might the calculated LDL-C be unreliable?

Accepted Answer

Triglycerides exceed 200 mg/dL, reducing accuracy

Answer

The Friedewald equation becomes unreliable when triglycerides exceed 200 mg/dL and is invalid above 400 mg/dL because VLDL-C estimation (TG/5) is inaccurate at elevated TG levels.

Question 2

Which lipoprotein fraction is most directly measured in a standard fasting lipid panel rather than calculated?

Accepted Answer

HDL cholesterol

Answer

HDL cholesterol is directly measured via precipitation or homogeneous assay methods, whereas LDL-C and VLDL-C are typically calculated from measured values.

Question 3

A non-fasting lipid panel is acceptable for initial cardiovascular risk screening primarily because which value is least affected by a recent meal?

Accepted Answer

HDL-C

Answer

HDL-C remains relatively stable after meals and is the least postprandially affected major lipid fraction, making non-fasting panels useful for initial screening.

Question 4

A patient has TG of 650 mg/dL. Which parameter on the lipid panel can still be reliably used to guide statin therapy initiation?

Accepted Answer

Non-HDL cholesterol

Answer

Non-HDL cholesterol (total cholesterol minus HDL-C) is directly calculated from measured values and remains valid regardless of triglyceride levels, making it the preferred treatment target when TG exceed 400 mg/dL.

Question 5

In a patient with familial hypercholesterolemia, which lipid panel finding is most characteristic?

Accepted Answer

Severely elevated LDL-C with relatively normal triglycerides and HDL-C

Answer

Familial hypercholesterolemia is characterized by dramatically elevated LDL-C (often >190 mg/dL in adults) due to defective LDL receptor function, with triglycerides and HDL-C typically in the normal range.

(CLS) Clinical Lipid Specialist Certification Practice Test

(CLS) Clinical Lipid Specialist Certification Practice Test

CLS Lipid Panel Interpretation 2