Evaluation of the MycoDot™ test for the diagnosis of tuberculosis in HIV seropositive and seronegative patients

Abstract

SETTING: Patients were recruited from Siriraj, Bamrasnaradura, and Central Chest Hospitals, the three major hospitals responsible for tuberculosis patients in Bangkok, Thailand, and vicinity. OBJECTIVE: To evaluate a new rapid serologic test, the MycoDot™ test, for diagnosis of tuberculosis (TB). DESIGN: The study was conducted as a cross-sectional survey. A total of 594 patients were tested with the MycoDot™ test. This included 142 human immunodeficiency virus (HIV) seropositive patients with active TB, 144 HIV seronegative patients with active TB, 153 HIV seropositive controls, and 155 HIV seronegative controls. RESULTS: The sensitivity of the MycoDot™ test for detection of TB was 40.1% in HIV seropositive patients, compared with 63.2% in HIV seronegative patients (P < 0.001). If only patients with laboratory proven TB were evaluated, the sensitivity was 40.6% in seropositive and in 70.8% seronegative patients. The sensitivity of the MycoDot™ test was similar in TB patients with pulmonary and extra-pulmonary disease. The sensitivity of the test in patients with CD4 counts ≥200 cells/mm3was significantly higher than in those with CD4 counts <200 cells/mm3. The specificity of the test was 97.4%, and was identical in HIV seropositive and seronegative individuals. CONCLUSION: The MycoDot™ test had a higher sensitivity for the diagnosis of TB among HIV seronegative than HIV seropositive patients. Although the MycoDot™ test has a less than optimal sensitivity, the test specificity approaches 100%. It may be useful in patients with suspected TB and negative smears and in extrapulmonary TB.