A simple blood protein test may outperform standard cholesterol screening — so why are nearly all Americans missing out on it?
Every year, millions of Americans roll up their sleeves for a routine cholesterol check. Doctors scan LDL — the so-called “bad” cholesterol — and use it as a primary barometer for heart disease risk. But a growing body of research suggests this standard approach may be leaving a dangerous blind spot, one that a relatively obscure blood protein test could illuminate.
That test measures apolipoprotein B, or apoB — a protein that coats every harmful fat particle circulating in the bloodstream. And according to a sweeping new review of the evidence, it may be a more precise predictor of cardiovascular risk than LDL alone. The catch: fewer than 1% of American adults have ever had their apoB levels checked.
What Is ApoB and Why Does It Matter?
Cholesterol doesn’t float freely through the blood. Instead, it travels inside microscopic packages called lipoproteins — and it’s those packages, not the cholesterol they carry, that doctors increasingly believe cause the most damage. ApoB is the protein found on the surface of each of those harmful packages, including low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL). Because every such particle carries exactly one apoB molecule, measuring apoB gives doctors an accurate tally of the total number of artery-clogging particles in the blood.
Heart disease remains the leading cause of death for both men and women in the United States. When LDL and VLDL particles embed in artery walls, they trigger inflammation and plaque buildup, progressively narrowing blood vessels and raising the risk of heart attack and stroke. Standard cholesterol panels reveal how much cholesterol those particles are carrying — but not necessarily how many particles there are.
The Hidden Problem With Normal LDL
Here’s where conventional screening can fall short: a person’s LDL number can appear perfectly normal while their apoB count remains dangerously elevated. Cardiologists call this discordance, and it’s not uncommon — particularly in people who are overweight, have diabetes, or carry elevated triglyceride levels.
In practical terms, LDL cholesterol reveals how much cholesterol is being transported by harmful particles, while apoB reveals how many of those particles exist. For patients with metabolic conditions, the gap between those two numbers can be clinically significant — and potentially lifesaving to detect.
Why ApoB Testing Remains Rare
Despite the compelling science, the American Heart Association does not currently recommend apoB testing as a routine part of cholesterol screening for the general public, reserving it primarily for patients with high triglyceride levels. A 2024 study sponsored by Regeneron and published in The American Journal of Preventive Cardiology found that fewer than 1% of U.S. adults have received the test.
The reluctance to mainstream the test is partly a matter of inertia — LDL has decades of research and clinical familiarity behind it — and partly a reflection of the absence of universally agreed-upon targets. Generally, apoB values below 90 mg/dL are considered acceptable in otherwise healthy adults, with some researchers advocating for lower thresholds closer to 70 mg/dL for those at higher cardiovascular risk.
When insurance doesn’t cover the test, the out-of-pocket cost at most labs typically runs around $70 — an accessible price for many patients, but one that adds friction when the test isn’t part of a standard order.
What Cardiologists Are Saying
There’s no shortage of physicians who believe the medical establishment needs to move faster on this. Dr. Ann Marie Navar, a preventive cardiologist at UT Southwestern Medical Center in Dallas, routinely orders apoB for all her patients and believes universal screening for adults is warranted. Dr. Samia Mora of Brigham and Women’s Hospital takes a similarly proactive stance, recommending that patients have the test done at least once to verify that their LDL numbers aren’t masking a higher particle burden.
Dr. Jeffrey Berger, a preventive cardiologist at NYU Langone, describes apoB as offering a practical and comprehensive way to assess overall cholesterol burden — capturing both the accumulation of harmful cholesterol and the formation of arterial plaque in a single number.
Dr. Michael Shapiro, chair of the American Heart Association Council on Lipidology, Lipoprotein, Metabolism & Thrombosis, sees the greatest immediate value in using apoB as a secondary check for patients already on cholesterol-lowering therapy — statins or otherwise. After reaching a target LDL level, an apoB measurement can help confirm whether the underlying particle count has truly been brought under control.
From Influencers to Salad Chains: ApoB Goes Mainstream
While academic medicine works through the policy thicket, popular health culture has already embraced apoB with enthusiasm. The test has become a fixture in wellness influencer circles and is increasingly available through direct-to-consumer lab companies. In a sign of how far this has spread into lifestyle territory, the Sweetgreen salad chain — which has cultivated ties to the anti-seed-oil wellness movement — recently partnered with the testing company Function Health to promote apoB screening alongside its menus.
For some cardiologists, the grassroots momentum is welcome, even if it’s arriving via unconventional channels. The more pressing concern, experts say, is that a significant slice of the population isn’t getting basic cholesterol screening at all. Research from Johns Hopkins University found that nearly a quarter of eligible adults in the U.S. haven’t been screened for cholesterol in the past five years — a gap that dwarfs even the underutilization of apoB testing.
The science on apoB is compelling and the cost of testing is modest. What’s needed now may simply be the collective will — among physicians, insurers, and patients alike — to make it a routine part of the conversation about heart health before it’s too late.
Source: NBC News
