Detection of Acid Fast Bacilli in Tuberculous Lymph Node Tissue and Touch Preparations—A Comparative Study

Abstract

Background: The most common form of extrapulmonary tuberculosis is lymphadenitis. Lymphadenitis is considered mainly a disease of young children and has a peak age of onset at 20 to 40 years. Objectives: The purpose of this study was to detect and compare the presence of acid fast bacilli in lymph node biopsies and their touch preparations using Ziehl Neelsen and fluorescence staining. Materials and Methods: The lymph node biopsies and their touch preparations were prepared and stained with Haematoxylin and eosin to determine their morphology. Slides were stained with ZN staining and fluorescent staining technique using Auramine O and Rohdamine B to demonstrate the presence of acid fast bacilli in tissue and their touch preparations. Results: AFB was detected in 56% of biopsies and 54% of touch preparations. In addition in these cases we observed that fluorescent staining technique using Auramine O and Rohdamine B is superior to ZN stain because low magnification used in fluorescent staining technique makes it possible to scan the smear rapidly and detects the AFB as glowing spots even if it is present in small numbers. Conclusion: The results of AFB in tissue biopsies are in equivalent in their touch preparation.