title: Tuberculin Skin Test and QuantiFERON(®)-TB Gold In-Tube Test for Diagnosing Latent Tuberculosis Infection among Thai Healthcare Workers.
abstract: A cross-sectional study was conducted on the performance of the tuberculin skin test (TST) and QuantiFERON(®)-TB Gold In-Tube test (QFT-IT) for detecting latent tuberculosis infection among Thai healthcare workers (HCWs). Each HCW underwent both the TST and QFT-IT during the annual health screening. Among the 260 HCWs enrolled, the median age was 30 years (range 19-60 years), 92% were women, 64% were nurses and nurse assistants, 78% were Bacillus Calmette Guérin vaccinated, and 37% had previously taken the TST. Correlation between TST reaction size and the interferon-γ level was weak (r = 0.29; P < 0.001). Of the HCWs, 38% and 20% had a reactive TST and a positive QFT-IT, respectively. Using QFT-IT positivity as a standard for latent tuberculosis diagnosis, the cut-off for TST reactivity with the best performance was ≥13 mm with a sensitivity, specificity, false positivity, and false negativity of 71%, 70%, 30%, and 29%, respectively (area under the curve 0.73; P < 0.001). The independent factor associated with a false reactive TST was a previous TST (adjusted odds ratio 1.83; P = 0.04). Our findings suggest that the QFT-IT may be the preferred test among HCWs with previous TST. In settings where the QFT-IT is not available, appropriate cut-offs for TST reactivity should be evaluated for use among HCWs.
authors.affiliation: Division of Infectious Diseases, Faculty of Medicine, Thammasat University.
authors.forename: Thana
authors.initials: T
authors.lastname: Khawcharoenporn
authors.forename: Anucha
authors.initials: A
authors.lastname: Apisarnthanarak
authors.forename: Somchai
authors.initials: S
authors.lastname: Sangkitporn
authors.forename: Janisara
authors.initials: J
authors.lastname: Rudeeaneksin
authors.forename: Sopa
authors.initials: S
authors.lastname: Srisungngam
authors.forename: Supranee
authors.initials: S
authors.lastname: Bunchoo
authors.forename: Benjawan
authors.initials: B
authors.lastname: Phetsuksiri
mesh_terms: D000328:Adult; D001500:BCG Vaccine / Q000008:administration & dosage*; D001681:Biological Assay; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D006282:Health Personnel; D006801:Humans; D007371:Interferon-gamma / Q000097:blood; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000276:immunology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification* / Q000502:physiology; D012680:Sensitivity and Specificity; D062606:Tertiary Care Centers; D013785:Thailand; D014374:Tuberculin Test; D014611:Vaccination
chemical_list: D001500:BCG Vaccine; D007371:Interferon-gamma