Patterns of Sexually Transmitted Infection-Related Testing and Diagnosis by Places of Service, MarketScan Commercial Claims Data, 2023-2024

Background: Understanding where people receive care for sexually transmitted infections (STI) is essential for optimizing STI service delivery. Methods: Based on the date of service, the first encounter with STI testing or diagnosis for each patient aged ≥15 years was identified using MarketScan commercial claims data from 2023-2024. We identified chlamydia, gonorrhea and syphilis testing using Current Procedural Terminology codes (CPT) and diagnoses using International Classification of Diseases (ICD-10) codes. Encounters were classified as diagnosis encounters if they included an STI diagnosis, and as testing encounters if they included STI testing only. We appropriately identified place-of-service using an encounter-ordering approach, especially tracing laboratory claims to their origin. Results: A total of 2,964,733 STI-related encounters (98.6% for testing, 1.4% for diagnoses) were identified, including 82.7% for chlamydia (CT), 81.3% for gonorrhea (GC), and 50.0% for syphilis (TP). Among the encounters, office encounters accounted for the highest proportion (82.1%), followed by independent laboratories (12.2%) and emergency room (ER)/urgent care (UC)/acute care (AC) clinics (4.8%). Based on demographic characteristics, encounters were more frequent among people aged 30-34 years old (17.9%), women (74.5%) and people living in the South region (47.4%). Conclusions: The predominance of STI testing-coded encounters indicates that most identified claims involved STI testing rather than diagnosis coding. However, claims data cannot distinguish routine screening from diagnostic testing and finding reflect encounter-based observations of claims, rather than inferring adherence to screening guidelines. Maintaining access to offices, independent laboratories, and ER/UC/AC clinics remains important for appropriate STI care.