What is the difference between the Friedewald and Martin-Hopkins equations for LDL-C?

The Friedewald equation estimates LDL-C using a fixed triglyceride-to-VLDL-C ratio of 5:1 (LDL-C = TC − HDL-C − TG/5). It performs well in typical cases but is most reliable when triglycerides are <150 mg/dL and LDL-C ≥70 mg/dL. Accuracy declines at higher triglycerides or lower LDL-C, where it tends to underestimate LDL-C due to limitations in VLDL-C estimation.
 
The Martin-Hopkins equation improves on this by replacing the fixed “/5” factor with an adjustable ratio based on triglyceride and non-HDL-C levels. Using a detailed stratification approach, it provides more accurate LDL-C estimates across a wider range of clinical scenarios, including nonfasting samples, low LDL-C, and elevated triglycerides.
 
Considering both methods can help providers better interpret LDL-C values across diverse patient profiles, reducing the risk of misclassification and supporting more precise lipid management decisions.