Evaluating the laboratory techniques used in the diagnosis of sputum-producing-patients suspected of Mycobacterium infection.

Because of the susceptibility of HIV-infected persons to Mycobacterial infections, more sensitive diagnostic technique are being employed to detect Mycobacterium spp from clinical specimens. This study was therefore carried out to evaluate the sensitivity of methods used for the diagnosis of mycobacterial infections among sputum producing patients. Sputum samples from 160 patients were examined for Mycobacterium spp using direct smear microscopy, concentrated smear microscopy, and cultural method. The cultural technique detected the highest number of positives, 62 (38.8%), followed by concentrated smear technique,, 41 (25.6%) while direct smear technique detected only 24 (15.0%). The results show that cultural technique should be employed for the diagnosis of Mycobacterium in order to avoid false negative results. However, concentrated smear technique should always be carried out, so that treatment could commence immediately in obviously positive cases.