Healthcare & Clinical
Sampson-NIH LDL-C Equation (Accurate LDL up to Triglycerides 800 mg/dL)
Calculate low-density lipoprotein cholesterol (LDL-C) in mg/dL using the 2020 Sampson-NIH bivariate quadratic equation—avoiding Friedewald's underestimation at low LDL-C or triglycerides up to 800 mg/dL.
Fix Friedewald's dangerous LDL-C underestimation when triglycerides exceed 150–400 mg/dL!
The classic 1972 Friedewald equation LDL = TC - HDL - (TG / 5) assumes a fixed 5:1 triglyceride-to-cholesterol ratio inside VLDL particles! Whenever triglycerides rise (200–800 mg/dL) or PCSK9/statin therapy drives LDL-C below 70 mg/dL, chylomicron remnants and TG-enriched VLDL make TG/5 overestimate VLDL-C—artificially depressing Friedewald LDL-C and causing premature undertreatment!
Calibrated directly against beta-quantification reference ultracentrifugation at the NIH, Sampson et al. (2020, JAMA Cardiology) derived the bivariate quadratic equation valid all the way to TG = 800 mg/dL: LDL-C = (TC / 0.948) - (HDL / 0.971) - ((TG / 8.56) + ((TG * NonHDL) / 2140) - (TG^2 / 16100)) - 9.44, where NonHDL = TC - HDL (all in mg/dL)! At TC = 220, HDL = 42, TG = 350 mg/dL, Friedewald reports 108.0 mg/dL, whereas Sampson-NIH accurately reveals 117.0 mg/dL (+9 mg/dL higher atherogenic LDL)!
| Lipid Panel (mg/dL) | Sampson-NIH LDL-C | Legacy Friedewald (TC-HDL-TG/5) | Clinical Validity |
|---|---|---|---|
| TC 220, HDL 42, TG 350 | 117.0 mg/dL | 108.0 mg/dL (Underestimates by 9!) | Valid (TG <= 800 mg/dL) |
| TC 190, HDL 55, TG 120 | 113.6 mg/dL | 111.0 mg/dL | Concordant at normal TG |
| Severe Chylomicronemia (TG = 950) | Guarded (> 800 mg/dL) | Invalid (> 400 mg/dL) | "Direct Ultracentrifugation Required (TG > 800)" |
Sampson-NIH (2020) LDL-Cholesterol Formula (mg/dL, Valid for TG <= 800)
Evaluates the NIH beta-quantification-calibrated quadratic LDL-C formula and guards against TG > 800 mg/dL or HDL >= TC.
=IF(OR(B2 <= 0, B3 <= 0, B4 <= 0, B3 >= B2), "Invalid Lipid Panel", IF(B4 > 800, "Direct Ultracentrifugation Required (TG > 800)", ROUND((B2 / 0.948) - (B3 / 0.971) - ((B4 / 8.56) + ((B4 * (B2 - B3)) / 2140) - ((B4 ^ 2) / 16100)) - 9.44, 1)))Non-HDL Cholesterol = TC - HDL (mg/dL, Triglyceride-Independent ApoB Proxy)
Computes Non-HDL cholesterol across all atherogenic lipoproteins regardless of fasting state.
=IF(OR(B2 <= 0, B3 <= 0, B3 >= B2), "Invalid Lipid Panel", ROUND(B2 - B3, 1))Try the example
Use the original values or change them to test your understanding.