Identifying the risk of cardiovascular disease can help individuals take measures that lower their odds of an adverse event, such as a myocardial infarction (heart attack) or stroke, in the future.

Conventional laboratory tests for assessing the risk of cardiovascular disease evaluate blood levels of high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides.

While these tests are essential to identifying potential disease, new science from Quest Diagnostics and other researchers suggest that measuring blood levels of these biomarkers provides an incomplete picture. The size and activity of the particles that form cholesterol, not just the amount of it, also influence risk.

HDL cholesterol is not always “good”
Too much cholesterol on the walls of arteries causes a process called atherosclerosis, a form of cardiovascular disease. HDL is sometimes called “good” cholesterol because it can help to remove cholesterol from artery walls.

For this reason, medical experts have long believed that high amounts of HDL, and low amounts of LDL (as well as total cholesterol and triglycerides), in the bloodstream signify low risk of disease.

Yet, a growing body of research shows that the function HDL is a more important predictor for reducing atherosclerosis and a better marker of disease risk. Quest researchers have demonstrated how the proteins that make up HDL (apoproteins) relate to HDL function.  The makeup of these particles can vary by individual.

Assessing the function of HDL (called cholesterol efflux capacity or CEC) has traditionally involved sophisticated laboratory cell culturing, limiting its use in medical practice.

That may be about to change.

Testing for HDL Function
According to recent studies, a novel laboratory “HDL function” test that analyzes several apolipoproteins may provide important insights into cardiovascular disease risk.  The test was developed by scientists from Quest Diagnostics and its Cleveland HeartLab cardiometabolic center of excellence,

In early 2019, the Journal of American College of Cardiology published a study that found that the HDL function test may be independently associated with cardiovascular death in individuals with coronary artery disease. The study evaluated 954 individuals. [i]

And at the 2019 American Heart Association Scientific Sessions in mid-November, scientists from Cleveland HeartLab presented new data that found that the test provides “weak, but significant correlation” with several markers associated with cardiovascular risk (including HDL, LDL, and insulin blood levels), thereby providing “novel and unique information above what current tests offer to define a patient’s risk.”

“This study provides tantalizing evidence that HDL function testing will complement other methods of evaluating an individual’s cardiovascular health, enhancing risk detection and patient management,” said study co-author Marc Penn, MD, PhD, FACC, Founder, Cleveland Heart Lab, and Medical Director, Cardiometabolic Endocrine Division, Quest Diagnostics.

The HDL Function test is expected to be available nationally in 2020. It will be the first significant innovation to emerge from Cleveland HeartLab since the company was acquired by Quest Diagnostics in December 2017.

[i] Natarajan P, Lyass A, Li Y, et al. Association of an HDL apolipoproteomic score with the presence of coronary atherosclerosis and incident cardiovascular death. J Am Coll Cardiol. 2019; 73:2135-2145.