Atherogenic index (TC/HDL)
What it measures, and what changes the number.
The atherogenic index shown here is a calculated value: total cholesterol divided by HDL cholesterol. It is not measured on its own but derived from two results in the same lipid panel, giving a single figure that expresses how total cholesterol compares with the HDL fraction.
Because it comes from them, it is always read with total cholesterol and HDL cholesterol, and often next to other ratios such as LDL/HDL and triglycerides/HDL, plus non-HDL cholesterol.
Anything that shifts either input shifts the ratio, including whether the sample was fasting and the method the lab uses for HDL. Labs may print it as CHOL/HDLC RATIO, Total Cholesterol/HDL Ratio or Índice Aterogénico CT/HDL.
Often read alongside: Total cholesterol, HDL cholesterol, LDL/HDL ratio, Triglycerides/HDL ratio, Non-HDL cholesterol