Comparision of pap stained smears by using auto fluorescence method with ziehl-neelsen method for detection of acid fast bacilli (AFB)

Abstract

The Ziehl-Neelsen staining method though it plays an important role in detecting acid fast bacilli (AFB) by direct microscopy its low sensitivity makes to look for the other alternatives. : This study was undertaken to evaluate the utility of auto fluorescence method on Papanicolaou stain (Pap) in comparison tothe traditional Ziehl-Neelsen stain (ZN) method in detection of AFB from lymph node aspirates. Fine needle aspirations (FNAs) were done in 153 patients with clinical suspicion of tubercular lymphadenitis. Smears from aspirate were processed for routine cytology for Hematoxyllin & Eosin (H&E), Giemsa, Pap, Ziehl-Neelsen (ZN) and Auramine (AR) staining. Pap stained smears were examined for AFB for their autofluorescence under fluorescent microscope using the blue excitation filter. ZN stained smears are examined for AFB under oil immersion of compound microscope. The efficacy of the autofluorescence method by Pap in detection of acid fast bacilli (AFB) over the conventional Ziehl-Neelsen stain was analyzed by taking AR as a standard control for AFB.Tuberculous lymphadenitis was diagnosed in 36 cases out of 153 clinicall suspected cases by cytology, culture and microscopyThe sensitivity of ZN was 57.14% and specificity was 99.15% while the sensitivity of AF was 96.5% and the specificity was 91.8%. : It was a novel method of detection of AFB, cheaper, easily available and less time consuming than other methods. AR also had high sensitivity rates as AF.