Gaps and disparities in Lp(a) testing before universal screening: A 10-year analysis.

BACKGROUND: Lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD), yet testing remains underutilized. Updated guidance now recommends once-per-lifetime Lp(a) testing in all individuals. We evaluated Lp(a) testing utilization from 2016 to 2025, to identify gaps, disparities and overall trends in testing utilization. METHODS: Retrospective cohort study of lipid-tested patients from 2016 to 2025. Lp(a) testing rates were calculated among lipid-tested patients. Multivariable logistic regression identified predictors of testing, and interrupted time-series (ITS) was used to assess trends in testing rates. RESULTS: Among 1,009,102 lipid-tested patients, 75,021 (7.4%) underwent Lp(a) testing; 80.9% for primary prevention, 55% male. Males were more likely to be tested (OR 1.24, 95% CI 1.22-1.26). ASCVD was an independent predictor for testing (OR 1.38, 95% CI 1.35-1.41), driven by coronary artery disease alone (OR 1.74); while other ASCVD subtypes were associated with decreased odds of testing. Age was also predictive of Lp(a) test (OR 1.06 per 10 years, 95% CI 1.05-1.06). ITS revealed an immediate 58.8% increase at Q4 2021 (IRR = 1.588, 95% CI: 1.047-2.409), with a sustained 3.1% quarterly increase thereafter (IRR = 1.031, 95% CI: 1.008-1.056). CONCLUSIONS: Lp(a) testing has substantially grown over the past decade, however important gaps and disparities in testing utilization were identified. Males are tested more frequently than females, individuals with non-CAD ASCVD subtypes are less likely to be tested, and testing preferentially reaches older patients. With updated guidance, future efforts must prioritize broader testing adoption, while addressing gaps in utilization.