Diagnostic value of an immunochromatographic test over clinical predictors for tuberculosis in HIV patients

• Main Authors: Nanta S, Kantipong P, Pathipvanich P, Ruengorn C, Tawichasri C, Patumanond J
• Format: Article
• Language: English
• Published: Dove Medical Press 2011-09-01
• Series: Clinical Epidemiology
• Online Access: http://www.dovepress.com/diagnostic-value-of-an-immunochromatographic-test-over-clinical-predic-a8273

Sirisak Nanta1,2, Patcharee Kantipong3, Panita Pathipvanich4, Chidchanok Ruengorn5, Chamaiporn Tawichasri1, Jayanton Patumanond11Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; 2Maesai District Hospital, Maesai, Chiang Rai, Thailand; 3Chiang Rai Regional Hospital, Chiang Rai, Thailand; 4Lampang Regional Hospital, Lampang, Thailand; 5Department of Pharmaceutical Care, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, ThailandPurpose: The value of an immunochromatographic test for tuberculosis (ICT-TB) combined with clinical predictors has yet to be evaluated in Thailand. This study aimed to assess any additional diagnostic value of an ICT-TB test over that of clinical predictors in a group of human immunodeficiency virus (HIV) patients as well as in subgroups of HIV patients classified by clinical risk scores.Patients and methods: An extended cross-sectional study was conducted at a community hospital in Chiang Rai and a general hospital in Lampang. HIV patients registered between April 2009 and May 2010 were screened by a locally made ICT-TB test, including 38, 16, and 6 kD Microbacterium tuberculosis antigens, as well as by routine evaluations for TB diagnosis. Demographic data, medical history, signs, and symptoms were recorded. Participants were followed up for 2 months for final ascertainment of TB diagnosis.Results: Of 206 patients, 37 (18%) had TB. Four clinical predictors were identified: low body mass index (<19 kg/m2), prolonged cough (duration >2 weeks), shaking chills (≥1 week), and no use of antiretrovirals. The area under the receiver operating curve was 90.2%; adding the ICT-TB test result increased the area nonsignificantly to 91.6% (P = 0.40). When patients were categorized by risk scores derived from selected clinical predictors into low (scores ≤7) and high (scores >7) TB risk groups, a positive ICT-TB test increased the positive predictive value nonsignificantly in the low risk group (from 12.5% to 27.3%, P = 0.17) and the high risk group (from 78.6% to 80.8%, P = 0.73).Conclusion: In this study setting, the ICT-TB test did not enhance TB diagnosis over the four clinical predictors in the overall group or any subgroups of HIV patients classified by clinical risk scores.Keywords: diagnostic test, signs, symptoms, TB