Comparison of the diagnostic value of sputum smears using light and fluorescent microscopy with and without hypochloritesodium in patients with suspected pulmonary tuberculosis

Backgrounds:Tuberculosis is an infectious disease transmitted by bacteria called Mycobacteriumtuberculosis. The gold standard for diagnosis of pulmonary tuberculosis is sputum culture insolid media that usually become positive between 3 to 8 weeks. Sensitivity of direct sputumsmear is approximately 70% at the best conditions. A variety of methods were used toenhance the sensitivity of direct sputum smear. The purpose of this study is to compare thediagnostic value of sputum smear with and without sodium hypochlorite using light andfluorescent microscopy in patients suspected of pulmonary tuberculosis referring to Boo-AliHospital (1390-91).Materials and Methods:In this cross - sectional study 195 patients with suspected pulmonary tuberculosis referring toBoo-Ali Hospital in Zahedan were studied during 1390-1391. Three consecutive sputumsamples were taken from each patient. All specimens were examined for direct microscopicexamination with both Zeil-Nelson and auramine rhodamine staining methods with andwithout adding sodium hypochlorite and they are also cultured in lowenstein jensen media.Comparison between several methods was done to obtain the diagnostic values of the tests.Result:The results of the study revealed that sputum culture was positive in 76 (38%) of thespecimens. In direct smear staining with Ziehl-Nelson without hypochlorite sodium, 63patients (32%) and with adding hypochlorite sodium, 69 patients (35%) were positivecomparing to culture. Staining with uramine rhodamine without and with adding hypochloritesodium were positive in 66 (33%) and 71 (36%) of the patients, respectively. Usingfluorescent microscopy comparing to light microscopy with and without sodium hypochloriteincreases the diagnostic value of direct smear without any statistical significant difference.Adding hypochlorite sodium also increases the sensitivity of the tests but no statisticalsignificance was observed.Conclusion:The diagnostic value of direct sputum smear microscopy with sodium hypochlorite washigher than direct sputum smear microscopy without sodium hypochlorite. Regarding thatdirect microscopic smear remains the currently applied, simple and non expensive diagnosticmethod in low-income countries, further studies are necessary to improve the diagnosticvalue of sputum smears.

Keywords:

Sodium Hypochlorite , Light Microscopy , fluorescent microscopy diagnosis value , Tuberculosis