Comparision of Ziehl-Neelsen and Fluorescence Microscopyfor Diagnosis of Tuberculosis

Abstract

Tuberculosis(TB) is a serious threat to human health and is a global concern.Nepal isone of the endemic countries to TB and hence early detection of cases can be milestoneto limit the spread of disease.A comparative study was conducted inMicrobiologyLaboratory, Bir Hospital to develop improved strategy for laboratorydiagnosisof AcidFast Bacilli (AFB) in suspectedTB patients. A total of 2,592 different specimens(pulmonary 2,492, extra pulmonary 100) from 1,019 suspects visiting Bir Hospital,were included in the study.ZN and Fluorescence microscopy methodswereapplied ineach specimen for acidfaststaining. The total positive yield from the 2,592specimenswas slightly higher by Fluorescence microscopy160 (6.17%) as against 140(5.4%)positive by the Z-N microscopy. The higher proportion of positive results seen influorescence microscopy than in ZN microscopy was found statistically significantdifference (p < 0.05). Among suspects of 2,492 different specimens for pulmonary tuberculosis, 155werefound AFB positive byeitherof the method. Out of 155positive cases of TB, 133caseswere found to be positive by ZN microscopyand 153by Fluorescence microscopy.Whereas among 100 suspects of extra pulmonary tuberculosis, both ZN microscopy andFluorescence microscopy gave same results (i.e. 7 positive cases). It was found that the sensitivity of Fluorescence microscopygreatly improves thediagnosis of TB.Furthermore, this method is also simple, easy andfast for low incomelaboratories with high sample load. Keywords: AFB, ZN microscopy, Fluorescence microscopy, Tuberculosis,Diagnosis.