Utility of quantitative analysis of urine lipoarabinomannan in the diagnosis of tuberculosis

BackgroundUrinary lipoarabinomannan (LAM) detection is a promising approach for the rapid diagnosis of active tuberculosis (TB).ObjectiveTo assess the diagnostic accuracy of urine LAM among TB patients either pulmonary or extra pulmonary.MethodsThis study was carried out on 85 cases (46 male and 39 female) with active tubercular infection divided into three groups; pulmonary (n = 40), extra pulmonary (n = 30) and disseminated tuberculosis (n = 15). Twenty-five normal individuals were included as the control group. LAM level was measured in urine by enzyme-linked immunosorbant assay (ELISA).ResultsTB Patients with disseminated disease had a higher urine LAM level (1.75 ± 1.65 ng/ml) than that for patients with pulmonary (0.58 ± 0.53 ng/ml) or extra pulmonary TB (0.17 ± 0.11 ng/ml) (P < 0.001). Patients with smear positive specimens had a higher urine LAM level (0.63 ± 0.54 ng/ml) than that of smear negative (0.040 ± 0.06 ng/ml) (P < 0.001). Quantitative urine LAM test results positively correlate with the degree of bacillary burden. Advanced age, immunosuppressant state and advanced radiological lesion were significant factors that were associated with higher quantitative urine LAM (P < 0.05).ConclusionUrine LAM test is a simple, rapid, and reliable diagnostic modality for active pulmonary or extra pulmonary tuberculosis. Quantitative LAM detection results increased progressively with bacillary burden and immunosuppression. Patients with disseminated TB are target populations for urine LAM detection.