CLS Study Guide 2026
Everything you need to pass the CLS exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 CLS Exam Format at a Glance
📚 CLS Topics to Study (69)
✍️ Sample CLS Questions & Answers
1. The mechanism by which evolocumab reduces LDL-C in HeFH patients includes which of the following?
Evolocumab is a monoclonal antibody that binds PCSK9 in plasma, preventing PCSK9 from binding and targeting LDL receptors for lysosomal degradation, thereby increasing receptor recycling.
2. What is the Friedewald equation limitation regarding triglycerides when calculating LDL-C?
The Friedewald equation (LDL = TC − HDL − TG/5) becomes unreliable when triglycerides exceed 400 mg/dL because the VLDL estimate is inaccurate.
3. What role does smoking cessation play in cardiovascular risk?
Smoking cessation significantly reduces cardiovascular risk by improving endothelial function, decreasing inflammation, and lowering blood pressure and heart rate. Within just a few years of quitting, the risk of heart attack and stroke drops substantially, eventually approaching that of a non-smoker. It is one of the most impactful lifestyle changes for cardiovascular health.
4. Which fibrate–statin combination carries the greatest risk of severe myopathy and rhabdomyolysis?
Gemfibrozil inhibits the glucuronidation pathway responsible for statin metabolism, raising statin plasma concentrations significantly and increasing the risk of myopathy and rhabdomyolysis; fenofibrate does not share this interaction.
5. Which omega-3 fatty acid formulation is FDA-approved at prescription doses specifically for severe hypertriglyceridemia (≥500 mg/dL)?
Both Vascepa (pure EPA) and Lovaza (EPA+DHA) are FDA-approved prescription omega-3 formulations for triglycerides ≥500 mg/dL.
6. Anorexia nervosa is associated with which lipid pattern?
Anorexia nervosa often paradoxically raises LDL-C and total cholesterol due to reduced bile acid production, decreased LDL receptor activity, and impaired reverse cholesterol transport.