P6‐46: Long‐term pass holders with multidrug‐resistant tuberculosis (MDR‐TB) in Singapore: missed opportunities for earlier diagnosis

Background: Singapore is an intermediate TB incidence country with a very low incidence of multidrug-resistant TB (MDRTB)among its local-born population. Foreign-born, long-term pass applicants/holders routinely undergo a chest x-ray (CXR) to detect active TB prior to pass approval. Persons with CXR suspicious for TB are to be evaluated at the TB Control Unit(TBCU) with sputum mycobacteriological testing. Aim: To determine the findings of screening CXRs performed for pass application/renewal among foreign-born, long-term pass holders who were subsequently diagnosed with MDR-TB in Singapore between 2015-2018. Methods: The CXRs and their reports for pass application/ last pass renewal were obtained. Demographic and disease characteristics of cases with screening CXR findings which required further evaluation for active TB, but which was not undertaken (“screen failures”) were analyzed. Results: The images and/or reports of screening CXRs performed for pass application were available for 27 (61.3%) of 44 long-term pass holders diagnosed with MDR-TB. As ascertained by TBCU physicians, 19 (70.4%) were screen failures. Among these, the CXRs were reported as normal in 11, inactive TB in three, and to be compatible with active infection (without mention of TB) in five. Among the 19 screen failures, eight (42.1%) were migrant domestic workers and three (15.8%) worked in healthcare or education. Ten (52.6%) were smear positive at diagnosis. Nine (47.4%) were diagnosed with MDR-TB within two years of their long-term pass approval. Conclusions: There were many missed opportunities for earlier MDR-TB diagnosis among long-term pass holders in Singapore. Greater vigilance is needed to protect the community from the threat of TB.