Predictive lab test for cardiac events still rare but increasing

(Press-News.org) Researchers from University of California San Diego School of Medicine have found that testing for lipoprotein(a) — a genetic risk factor for heart disease — remains uncommon in the United States, despite modest increases over the past decade. The findings were published on Sept. 26, 2025 in the Journal of the American College of Cardiology: Advances.

Lipoprotein(a) — or Lp(a) — is a type of cholesterol particle in the blood. Elevated levels are strongly linked to a higher risk of heart attack, stroke and aortic valve disease. Roughly 20% of the U.S. population has elevated Lp(a), yet testing rates have historically been low.

In the new study, researchers analyzed records from Epic Cosmos, a national database that includes over 300 million patient records from health systems across all 50 states. This is the first published study to assess this volume of patients at this scale and the first to use Epic Cosmos in the University of California system.

They found that between 2015 and 2024, just 728,550 patients, representing only 0.2% of the U.S. population, underwent Lp(a) testing. Testing increased from about 14,000 patients in 2015 to more than 300,000 in 2024, but overall rates remain far below what experts recommend for identifying individuals at risk.

As an early predictor of heart disease, European countries are pushing toward universal testing. The U.S. is far behind this goal.

“By analyzing national data from over 300 million patients, we’ve uncovered how much work remains to bring Lp(a) testing into routine care,” said Mattheus Ramsis, M.D., lead author and assistant professor of medicine at UC San Diego School of Medicine. “These insights give us a roadmap for expanding access and addressing gaps. We’re seeing a growing recognition among clinicians of the importance of Lp(a) testing, but the low overall testing rates and regional imbalances highlight how much further we need to go. Broader awareness and access to testing could make the difference between catching disease early and missing an opportunity to prevent heart attacks and strokes, ensuring that all patients benefit from emerging therapies.”

The analysis revealed notable differences among groups. Testing was most common among adults ages 50 to 65, and testing rates were nearly equal between men and women. However, stark racial and ethnic differences were observed: less than 10% of those tested were Black, and only 7% identified as Hispanic or Latino, despite both groups being disproportionately affected by cardiovascular disease. Most testing occurred among white patients.

Geographic differences were also pronounced. California, Ohio and Texas accounted for the largest share of tests, together representing more than a quarter of the national total. Some states had almost no uptake of Lp(a) testing, underscoring the uneven spread of awareness and clinical practice across the country.

The study also found a shift in how tests are being conducted. In 2015, most measurements used older “mass-based” assays, which measure the total weight of Lipoprotein(a) in a blood sample. However, by 2024, two-thirds of tests were performed using the more accurate molar assays, in line with evolving clinical guidelines. Molar assays measure the actual number of Lp(a) particles in a person's bloodstream to assess cardiovascular disease risk, rather than just the mass of particles.

Lp(a) is unique among cholesterol particles because levels are determined almost entirely by genetics and remain stable throughout life. Unlike low-density lipoprotein (LDL) cholesterol, Lp(a) does not respond to diet or lifestyle changes, and no widely available therapies currently exist to lower it. However, several treatments are now in late-stage clinical trials. Experts suggest that broader adoption of testing could help identify high-risk patients who may benefit from these upcoming therapies.

Despite increasing awareness, testing remains rare. National guidelines currently recommend at least one lifetime Lp(a) test for adults, especially for those with a family history of premature cardiovascular disease. Still, with fewer than 1 in 500 Americans receiving the test annually, the UC San Diego team says there is much work to do.

“The rise in testing is encouraging, but we are still far from where we need to be,” said study co-author Ehtisham Mahmud, M.D., professor of medicine and Edith and William Perlman Endowed Chair in Cardiology, chief of the Division of Cardiovascular Medicine and executive director of the Cardiovascular Institute at UC San Diego. “If we want to close the gaps in cardiovascular risk assessment, especially in underserved communities, we need broader education, clearer guidelines and consistent insurance coverage for Lp(a) testing.”

The researchers emphasize that their study is not just about testing rates but about equity. Because cardiovascular disease remains the leading cause of death in the U.S., ensuring that all populations have access to emerging diagnostic tools is critical.

Future research will explore why some populations and regions lag in adopting Lp(a) testing. The UC San Diego team also hopes to study how testing patterns evolve as new Lp(a)-lowering therapies enter clinical practice in the next several years.

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Link to full study: https://www.sciencedirect.com/science/article/pii/S2772963X25006325

Additional co-authors on the study include: Mustafa Naguib, Marissa Dzotsi, M.P.H., Michael Wilkinson, M.D., Ehtisham Mahmud, M.D., Pam Taub, M.D. and Harpreet S. Bhatia, M.D., M.A.S. from UC San Diego.

The study was partly funded by the UC San Diego BEACON Center for Health Data Science.

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