Tuberculin skin test versus QuantiFERON-TB Gold In-tube assay in healthcare workers.
Cummings-KJ; Smith-TS; Shogren-ES; Khakoo-R; Nanda-S; Bunner-L; Smithmyer-A; Soccorsi-D; Kashon-ML; Mazurek-GH; Friedman-LN; Weissman-DN
Am J Respir Crit Care Med 2009 Apr; 179(Meeting Abstracts):A4103
Introduction: Healthcare workers (HCWs) are at risk for tuberculosis (TB) infection and have traditionally been screened with the tuberculin skin test (TST). Newer interferon-gamma release assays may have advantages over TST, but comparative studies in U.S. HCWs are lacking. We aimed to compare TST and QuantiFERON-TB Gold In-Tube (QFT-GIT) results among newly hired HCWs in a state with a low TB incidence. Methods: We invited HCWs undergoing TST to complete a questionnaire and have 2 QFT-GITs, before and after TST. TST was interpreted according to current guidelines and QFT-GIT according to the manufacturer's instructions. We calculated TST and first QFT-GIT agreement and specificity, and examined QFT-GIT reproducibility. We confirmed indeterminate and positive results by repeating ELISAs. We compared acceptability and operational costs. Results: Of 182 participants, 96% were US-born; 7% received BCG. TST was positive in 4 (2%) and first QFT-GIT in 3 (2%). Overall agreement was 96%, but agreement when one of the tests was positive was 0%. For the 112 (62%) without TB risk factors, specificity of TST was 99% and of first QFT-GIT was 98%. Two participants with a negative first QFT-GIT had a positive second QFT-GIT. Only 2 of the total of 5 positive QFT-GIT results could be confirmed. Participants reporting diabetes or recent immunosuppressive therapy had a non-significant seven-fold higher odds of confirmed indeterminate QFT-GIT. QFT-GIT had higher acceptability and material costs than TST. Conclusions: QFT-GIT is a reasonable screening option for HCWs in low incidence settings. Agreement between TST and QFT-GIT was high, but the tests did not agree on positives. Repeating ELISAs was useful when QFT-GIT was positive.
Epidemiology; Exposure-assessment; Exposure-levels; Exposure-methods; Health-care-personnel; Occupational-exposure; Occupational-hazards; Occupational-health-programs; Questionnaires; Standards; Statistical-analysis
American Journal of Respiratory and Critical Care Medicine