Bleach treatment of sputum samples aids pulmonary tuberculosis screening among HIV-infected patients in Laos

BACKGROUND: Laos has a high prevalence of tuberculosis (TB) and a slowly increasing prevalence of human immunodeficiency virus/acquired immune-deficiency syndrome (HIV/AIDS). Sputum smear microscopy is the only method currently available for routine screening of pulmonary TB, although it only detects one in three cases among persons living with HIV (PLWH). Bleach treatment of sputum samples (bleach method) has been shown to significantly improve the sensitivity of the test; however, its effectiveness in PLWH remains to be determined in Laos. OBJECTIVES: To determine the performance of the bleach method as a diagnostic tool for pulmonary TB in PLWH and to assess its cost-effectiveness in Laos. RESULTS: Of 174 sputum samples collected from 92 patients, 29 were culture-positive for Mycobacterium tuberculosis in 17 patients. The sensitivity of the direct method and the bleach method was respectively 59% and 93%, and specificity was 100% for both methods. The incremental cost-effectiveness ratio for screening an additional case was US$17.40. CONCLUSION: The bleach method is simple, cheap, easy to perform and cost-effective in PLWH. Its implementation in laboratories involved in routine screening of pulmonary TB among PLWH would allow practitioners to start the treatment of this life-threatening co-infection earlier.