UPDATED: New Equation for Low-Density Lipoprotein Cholesterol Calculation at Stanford Health Care
ORDER CODE: LCDPC, LPDC
SUMMARY
Effective February 1, 2021, the National Institutes of Health (NIH) equation (below) will replace the Friedewald equation for all lipid panels that report calculated low-density lipoprotein cholesterol (LDL-C) (1,2). The NIH calculation provides a more accurate LDL-C result than the Friedewald equation, particularly in patients with low LDL-C concentrations (< 70 mg/dL) (1,2). The NIH equation gives valid LDL-C results with triglyceride (TG) concentrations up to 800 mg/dL (1,2). When the triglyceride concentration is >800 mg/dL, the LDL-C will not be calculated, and a direct LDL-C should be ordered.
The NIH equation performs equally well in both fasting and non-fasting states.
NIH equation:
LDL-C = TC/0.948 – HDL-C/0.971 – (TG/8.56 + [TG x NonHDL-C]/2140 – TG2/16100) – 9.44
The following algorithm is implemented for the reporting of calculated LDL-C values:
- A TG value up to 800 mg/dL; the LDL-C will be reported using the NIH equation.
- When the TG value is >800 mg/dL, the LDL-C will NOT be reported.
References
- Sampson M, Ling C, Sun Q, Harb R, Ashmaig M, Warnick R, Sethi A, Fleming JK, Otvos JD, Meeusen JW, Delaney SR, Jaffe AS, Shamburek R, Amar M, Remaley AT. A New Equation for Calculation of Low-Density Lipoprotein Cholesterol in Patients With Normolipidemia and/or Hypertriglyceridemia. JAMA Cardiol. 2020 Feb 26;5(5):1-9.
- Sathiyakumar V, Blumenthal RS, Elshazly MB. New information on accuracy of LDL-C estimation. American College of Cardiology. March 20, 2020. Accessed August 14, 2020. https://www.acc.org/latest-in-cardiology/articles/2020/03/19/16/00/new-information-on-accuracy-of-ldl-c-estimation