NEW data from a 15-year study presented at the Conference on Retroviruses and Opportunistic Infections (CROI) in San Francisco reveals significant disparities in latent tuberculosis infection (LTBI) testing practices within the United States. The research, conducted by Kaiser Permanente Northern California (KPNC), analyzed electronic health records from over 6.5 million members between 2008 and 2023, uncovering critical insights into testing trends and gaps.
Despite LTBI being the primary driver of new tuberculosis (TB) cases in the U.S., the study found that only 21.4% of individuals were tested for LTBI during the 15-year period. Alarmingly, 76% of these tests were administered to individuals without any TB risk factors, indicating a misalignment with targeted testing guidelines. Conversely, populations at higher risk, particularly those born in TB-endemic countries, were under-tested. The testing rate for this group was 3.3 per 100 individuals in 2008, increasing marginally to 5.0 per 100 in 2023. Notably, individuals born in TB-endemic countries had a 25.2% lower prevalence of LTBI testing compared to U.S.-born individuals.
The study also highlighted that among those tested, 26.5% received an interferon gamma release assay (IGRA), a more specific test for LTBI. Individuals from TB-endemic countries were 61.7% more likely to receive an IGRA compared to their U.S.-born counterparts. Additionally, individuals with risk factors such as close contact with TB cases, homelessness, and HIV were more likely to undergo LTBI testing, with prevalence ratios of 2.66, 1.29, and 3.58, respectively.
These findings underscore a significant gap between evidence-based guidelines and clinical practice. Despite data indicating that 82% of all TB cases in California occur among individuals born in TB-endemic countries, current LTBI testing practices disproportionately under-test this high-risk population while over-testing individuals without any TB risk factors. This misallocation of resources may hinder TB elimination efforts and highlights the need for more targeted testing strategies.
For healthcare professionals, this study emphasizes the importance of adhering to CDC and state-specific guidelines for LTBI testing, focusing on high-risk populations to effectively prevent the progression to active TB disease. Implementing targeted testing and treatment strategies is crucial in the ongoing effort to eliminate TB in the United States.
Reference: Ledesma JR et al. Gaps in Latent Tuberculosis Infection Testing Practices: A 15-Year Serial Cross-Sectional Study. Abstract 3279. The Conference on Retroviruses and Opportunistic Infections (CROI), San Francisco, CA, USA, March 9-12, 2025.
Anaya Malik | AMJ
