Calculate the atherogenic index of plasma (AIP) from triglycerides and HDL cholesterol in mg/dL or mmol/L, as the log of their molar ratio.
Atherogenic Index of Plasma Formula
The Atherogenic Index of Plasma (AIP) is calculated as the base-10 logarithm of the triglyceride-to-HDL-cholesterol ratio after both measurements are expressed in mmol/L.
When a U.S. lipid panel reports mg/dL, the calculator converts triglycerides by dividing by 88.57 and HDL-C by dividing by 38.67 before taking the logarithm. A raw mg/dL ratio must not be inserted directly into the AIP formula because the two analytes use different conversion factors.
Example
For triglycerides of 150 mg/dL and HDL-C of 50 mg/dL, the converted concentrations are about 1.694 mmol/L and 1.293 mmol/L. Their molar ratio is about 1.310, so AIP is approximately 0.117.
Research Context and Limits
AIP was proposed as a research marker correlated with lipoprotein particle size. Cut points such as below 0.11, 0.11–0.20, and 0.21 or higher come from research frameworks; they are not universal diagnostic categories or treatment thresholds.
The 2026 ACC/AHA dyslipidemia guideline bases clinical decisions on full cardiovascular risk assessment, LDL-C and non-HDL-C goals, and selected measures such as ApoB and lipoprotein(a)—not AIP. Do not use AIP to diagnose disease or to change diet, alcohol use, supplements, or medication.
Sources
- Dobiášová and Frohlich, original AIP research formulation.
- 2026 ACC/AHA Guideline on the Management of Dyslipidemia.
