By now you should have heard from your doctor about your total and low-density lipoprotein (LDL) cholesterol levels and whether they are normal or high. Soon you’ll be hearing some new terms to describe the risks associated with your blood lipid and lipoprotein levels.

Most experts agree that LDL cholesterol deposited into the walls of arteries can form atherosclerotic plaques that, in turn, can lead to heart attacks and strokes. Present guidelines favor using LDL cholesterol levels to predict the risk of developing plaques, to judge when treatment is desirable, and to determine targets for treatment. Experts disagree, however, as to whether LDL cholesterol is the best blood test for these purposes.

Several studies indicate that two other blood tests, apo B and non-HDL cholesterol, may be better than LDL cholesterol at predicting your risk of developing plaques. Apo B, the protein associated with LDL, could be a better choice than LDL cholesterol because apo B measures the number of LDL particles, rather than the amount of cholesterol carried on LDL. Non-HDL cholesterol, calculated by subtracting the HDL cholesterol from the total cholesterol, has the advantage of including the highly atherogenic particles (intermediate-density lipoprotein, or IDL) that result from the breakdown of triglyceride-rich lipoproteins. Both apo B and non-HDL cholesterol measurements are particularly useful in people with high triglyceride levels. Another valuable predictor is a high ratio of total or LDL cholesterol to HDL cholesterol. 

Though you may see news articles stating that apo B and non-HDL cholesterol are better than LDL cholesterol, their advantages are marginal and apo B measurements add a small cost to the present standard lipid profile. At least in the near future, don’t look for these two new measurements to replace LDL cholesterol as the key test.