Up to 16% of individuals with normal low-density lipid (LDL) cholesterol levels may have dangerous lipid particles that put them at risk of adverse cardiovascular events, including a heart attack or stroke, finds a new study by experts from Johns Hopkins University and Quest Diagnostics. Yet, fewer than 2% of patients are tested for this marker, called Apolipoprotein B (ApoB).

At this year’s 75th Annual Scientific Session & Expo presented by the American College of Cardiology, researchers highlighted this underutilized but important cardiometabolic test by presenting data from over 1.3 million patients who received testing from Quest between 2017 and 2023.

Key findings showed:

1. Between 2021 and 2023, ApoB testing rates doubled to just 1.8% – an extremely low rate relative to standard lipid panel testing, suggesting many at-risk patients may not be receiving the test.
2. 16% of patients tested had ApoB values meaningfully higher than their LDL-C, indicating that individuals whose standard cholesterol panels appear normal may be carrying hidden cardiovascular risk.
3. Out of these patients, the discordance was most pronounced at low LDL-C levels and higher triglyceride levels, indicating that individuals at a ‘goal’ LDL-C level can still carry a significant residual particle burden.

“ApoB is a relatively inexpensive test to perform, but the insights the results offer have the potential to be extremely valuable,” added Sanjay B. Dixit, MD, Medical Director at Quest Diagnostics and co-author of the study. “This data reveals the limits of standard cholesterol testing. It’s time to see wider adoption of ApoB testing. This way, we can enable care to start with health, not sickness, illuminating a patient’s cardiovascular disease risk in its early stages.”

For the first time ever, in a recent guideline update, the American Heart Association recommends patients with risk factors for cardiometabolic disease be tested for ApoB. ApoB testing, which helps identify size of particles which influence risk, can help assess risk for cardiovascular disease and guide decisions on lipid-lowering therapy.