Discrepancies in widely used serological methods to detect Borrelia infections may cause missed Lyme diagnoses

Accurate diagnosis of Lyme disease, caused by Borrelia burgdorferi, is essential for timely treatment and prevention of long-term complications. This study investigates discrepancies in widely used serological assays and their impact on diagnostic sensitivity in high-risk populations. We analyzed samples from an annual Lyme screening program conducted by Innatoss Laboratories between November 2020 and May 2022, targeting individuals with occupational exposure to ticks. A retrospective cohort of 60 positive serum samples from 57 participants (aged 23-64) was evaluated using three tier one protocols: EUROIMMUN/ZEUS ELISA, SERION ELISA, and Diasorin CLIA, followed by Viramed immunoblots for confirmation. Our findings revealed significant variability in test sensitivity: the EUROIMMUN/ZEUS protocol detected 96.8% of cases, compared to 84.1% for SERION (p = 0.023) and 69.8.0% for Diasorin (p<0.001). Notably, six recent Borrelia infections were missed due to test selection, as confirmed by longitudinal comparison with previous samples. One case study illustrated the clinical consequences of missed diagnoses, including delayed treatment and symptom persistence. These results underscore the need for standardized serological protocols and routine longitudinal sample comparison. We propose the establishment of a consensus panel to define assay performance criteria and recommend integration of electronic health records with laboratory systems to enable automated historical data retrieval. Adoption of more sensitive testing strategies and harmonized interpretation guidelines could significantly improve diagnostic accuracy and patient outcomes in Lyme disease. Summary boxO_ST_ABSWhat is already known about this subjectC_ST_ABSO_LILyme disease diagnosis relies heavily on serological testing. C_LIO_LIThe two-tier testing protocol is widely used but varies in sensitivity depending on the assays employed. C_LIO_LISerological tests cannot distinguish between past and recent infections without longitudinal data. C_LIO_LIHigh-risk populations, such as outdoor workers, benefit from regular Lyme screening to detect missed infections. C_LI What are the new findingsO_LISignificant discrepancies that exist between commonly used serological assays affect diagnostic outcomes. C_LIO_LISix recent Borrelia infections were missed due to the choice of test. C_LIO_LIComparing current results with previous samples from the same individual improves diagnostic accuracy. C_LI What is the possible impact of this study on clinical practice in the foreseeable future?O_LIIncreased awareness of test limitations may lead to earlier and more accurate treatment, reducing long-term complications. C_LIO_LIStandardization and harmonization of Lyme serology can improve future diagnostic guidelines and laboratory practices. C_LIO_LIRoutine comparison of longitudinal samples should become standard practice in Lyme screening programs. C_LI