[Evaluation of the acid-fast bacilli gradations before and after treatment of the expectorations by sodium hypochlorite [corrected] in the tuberculosis diagnosis]

To assess the impact of the sputum samples treatment by sodium hypochloride (NaOCl) 5% on the acid-fast bacilli (AFB) gradations in the tuberculosis diagnosis, 516 sputum samples were collected in 244 patients. The sputum smears made before and after expectorations treatment with NaOCl 5%, were stained by Ziehl-Neelsen hot method. The values obtained from the two microscopic readings were compared by using the chi2 test of McNemar. The statistical significance was set at p0.05. The results obtained before using NaOCl 5% showed that 357 samples were negative, while 41 were AFB scanty (gradation 1-9), 28, 40 and 50 were positive 1+, 2+ and 3+. After treatment, among 357 AFB negative expectorations, 14 (3.9%) were AFB-positive, while the AFB gradation increased for 77 (48.4%) in the 159 positive specimens. The two microscopic readings differ significantly (p = 0.001). The application of the process on a routine basis in the laboratory will require a reorganization of the tasks in order to give back the results to the patients in time. It is necessary to take into account the aspect of the samples.