title: Usefulness of the whole-blood interferon-gamma release assay for diagnosis of extrapulmonary tuberculosis.
abstract: The whole-blood interferon-gamma enzyme-linked immunosorbent assay (QuantiFERON-TB Gold [QFT-G]; Cellestis, Carnegie, Australia) has been studied mainly for diagnosing active pulmonary tuberculosis (TB) or latent TB. We prospectively evaluated its diagnostic usefulness in patients suspected with extrapulmonary TB (EP-TB). Of the 100 adult patients with suspected EP-TB, 43 were classified as "confirmed" EP-TB and 5 as "probable" EP-TB. Of the 48 with EP-TB, 27 (56%) were diagnosed with TB lymphadenitis and 11 (17%) with skeletal TB. The overall sensitivity and specificity of the assay were 69% (95% confidence interval [CI(95)], 53-81%) and 82% (CI(95), 69-91%), respectively. Among 44 patients presented with cervical lymphadenopathy, the QFT-G assay showed 86% (CI(95), 64-97%) sensitivity and 87% (CI(95), 66-97%) specificity, whereas in 28 with skeletal involvement, the sensitivity and specificity of the assay were 45% (CI(95), 17-77%) and 81% (CI(95), 54-96%), respectively. These suboptimal diagnostic performances suggest that the QFT-G assay alone is not sufficient for the diagnosis of EP-TB.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyoung-Ho
authors.initials: KH
authors.lastname: Song
authors.forename: Jae Hyun
authors.initials: JH
authors.lastname: Jeon
authors.forename: Wan Beom
authors.initials: WB
authors.lastname: Park
authors.forename: Sung-Han
authors.initials: SH
authors.lastname: Kim
authors.forename: Kyoung Un
authors.initials: KU
authors.lastname: Park
authors.forename: Nam Joong
authors.initials: NJ
authors.lastname: Kim
authors.forename: Myoung-don
authors.initials: MD
authors.lastname: Oh
authors.forename: Hong Bin
authors.initials: HB
authors.lastname: Kim
authors.forename: Kang Won
authors.initials: KW
authors.lastname: Choe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology* / Q000382:microbiology; D014388:Tuberculosis, Lymph Node / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology
chemical_list: D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma