If a lipid panel is ordered, what analytes must be analyzed after a 12-hour fast?

Prepare for the CAMLPR Chemistry Test. Enhance your understanding with interactive quizzes, flashcards, and detailed explanations. Boost your confidence and readiness for exam success!

Multiple Choice

If a lipid panel is ordered, what analytes must be analyzed after a 12-hour fast?

The key idea is that fasting is required to get an accurate triglyceride value, since eating can raise triglycerides and distort the panel. A lipid panel typically includes triglycerides and an LDL value (which is usually calculated from total cholesterol, HDL, and triglycerides). Because LDL is determined using triglycerides (LDL is often computed with the Friedewald equation: LDL ≈ TC − HDL − TG/5 when TG is below 400), you need the triglyceride measurement from the fasting sample to obtain the LDL value. Therefore, after a 12-hour fast, reporting triglycerides and LDL gives you the essential, reliable information in the panel. Total cholesterol and HDL can be measured without fasting, but the triglyceride value—and thus the LDL derived from it—are the parts that specifically require fasting.

The key idea is that fasting is required to get an accurate triglyceride value, since eating can raise triglycerides and distort the panel. A lipid panel typically includes triglycerides and an LDL value (which is usually calculated from total cholesterol, HDL, and triglycerides). Because LDL is determined using triglycerides (LDL is often computed with the Friedewald equation: LDL ≈ TC − HDL − TG/5 when TG is below 400), you need the triglyceride measurement from the fasting sample to obtain the LDL value. Therefore, after a 12-hour fast, reporting triglycerides and LDL gives you the essential, reliable information in the panel. Total cholesterol and HDL can be measured without fasting, but the triglyceride value—and thus the LDL derived from it—are the parts that specifically require fasting.

More practice questions