Agreement between TST and QuantiFERON-TB gold plus in diagnosing latent tuberculosis infection among exposed health care workers at a Malaysian teaching hospital

Incidence rates of tuberculosis (TB) infection among health care workers (HCWs) were always higher compared to the general population. The tuberculin skin test (TST), which was used to screen tuberculosis contact among HCWs has low specificity due to cross reaction with Bacille Calmette-Guerin (BCG) vaccination or nontuberculosis mycobacterium infection. QuantiFERON-TB Gold Plus (QFT-Plus) offered higher specificity since it used specific antigens to stimulate the production of interferon-gamma in the serum. QFT-Plus could help narrow down the treatment group for latent tuberculosis infection among HCWs. To determine the agreement between TST and QFT-Plus in diagnosing latent tuberculosis infection among exposed health care workers in Hospital Canselor Tuanku Muhriz. Between January and December 2020, 417 HCWs were screened for TB close contact, 157 had positive TST and 260 had negative TST results. HCWs from both TST groups were selected using a convenient sampling method, and QFT-Plus testing was performed on 107 consented HCWs. From 107 consented HCWs, 21 (19.6%) had positive QFT-Plus. Among the positive QFT-Plus participants, 14 (66.7%) had positive TST, and 7 (33.3%) had negative TST. Meanwhile, among 86 (80.4%) HCWs had negative QFT-Plus, 35 (40.7%) had positive TST, and 51 (59.3%) had negative TST. There was poor agreement between the tests (kappa = 0.163). Poor agreement between TST and QFT-Plus in diagnosing latent tuberculosis infection among exposed HCWs