International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2016): 79.57 | Impact Factor (2017): 7.296 Volume 7 Issue 6, June 2018 www.ijsr.net Licensed Under Creative Commons Attribution CC BY A Comparative Study of Fluorescence Microscopy with Ziehl Neelsen Staining for Detection of Acid Fast Bacilli in Lymph Node Aspirates Supreet Kaur Kalra, Surinder Paul, S.P. Singh Abstract: Objective : To study the cytomorphological features in fine needle aspiration smears from patients suspected of having tuberculous lymphadenitis using May Grunwald Giemsa (MGG) and Haematoxylin and Eosin stains and compare the efficacy of ZiehlNeelsen staining (ZN) and fluorescent staining for the detection of acid fast bacilli on lymph node aspirates. Materials and methods : The present study was conducted in 100 patients presenting with peripheral lymphadenopathy suspicious of tuberculous lymphadenitis. Fine needle aspirations were performed and smears from the aspirates were processed for routine cytology, the conventional ZN method, and the fluorescent method. Results : The smear positivity with ZN stain was seen in 37% of cases while the positivity increased to 73% with fluorescent method. Conclusion : Fluorescent microscopy has the advantage of speed and ease of screening, and reduces observer fatigue. The fluorescent method was found to be more advantageous than routine cytology and conventional ZN method, particularly in paucibacillary cases. Keywords: ZiehlNeelsen, Auramine-O, fluorescent microscopy, acid fast bacilli 1. Introduction Tuberculosis (TB) is an ancient infection that has plagued humans since times immemorial and continues to remain a major public health problem especially in developing countries like India. It has staged resurgence in the developed world due to HIV infection and multi drug resistance acquired by the infectious agent. This has prompted World Health Organization (WHO) to declare tuberculosis as a global emergency [1] . It causes ill-health in millions of people each year and in 2015 was one of the top ten causes of death worldwide, ranking above HIV/AIDS as one of the leading causes of death from an infectious disease [2] . TB manifests clinically as pulmonary or extrapulmonary tuberculosis (EPTB), with the former being more common. The last decade has witnessed shifting trends in tubercularinfection, with EPTB emerging as an important entity. It constitutes about 15–20% of all cases of tuberculosis in immunocompetent patients and accounts for more than 50% of cases in HIV positive individuals [3,4] . The term EPTB has been used to describe isolated occurrences of tuberculosis at body sites other than the lungs [5] , which includes the lymph nodes, pleura, bones, joints, brain, meninges, gastrointestinal organs, liver, genitourinary organs, peritoneum and pericardium. Lymphadenopathy is the most common presentation of extrapulmonary tuberculosis [6,7] . The lymph nodes commonly affected include cervical, axillary, inguinal and abdominal sites with cervical lymph nodes being the most commonly affected group of nodes reported [8] . The clinical parameters for the diagnosis of TB in lymph nodes are neither specific nor do their absence exclude TB involvement [9,10] . Fine-needle aspiration cytology (FNAC) of lymph nodes in TB has varied cytomorphological features. However, the conventional ZiehlNeelsen (ZN) method for acid-fast bacilli (AFB) plays a key role in the diagnosis and also for the monitoring of treatment in TB. Its major disadvantage is low sensitivity ranging from 20% to 43% [11,12] . Mycobacterial culture is the reference method for the detection of tubercle bacilli but it is time consuming and requires specialized safety procedures in laboratories. Serological techniques have the disadvantage of lack ofsensitivity and specificity [11] . Newer molecular techniques such as polymerase chain reaction (PCR), although rapid, are costly to be routinely used in developing countries where most TB cases occur [13] . Hence, a method for the identification of AFB which is more sensitive than the ZN method is required for early detection of cases. Thus arose the need for fluorescent staining. Fluorescent staining using auramine is already in vogue for detection of AFB on sputum smears under the RNTCP. Therefore, an attempt to apply similar knowledge to lymph node aspirates was made for faster detection of EPTB. 2. Material and Methods The present study was conducted in 100 patients presenting with peripheral lymphadenopathy suspicious of tuberculous lymphadenitis in the Department of Pathology, Government Medical College, Amritsar, after approval from the institutional thesis and ethics committee. Informed consent of the patient was taken. Relevant history of the patients was recorded as per a self- designed proforma. FNA was performed and the material was applied to pre labelled slides and stainedwith H&E, MGG, ZiehlNeelsen and Auramine - O stains for further evaluation. Depending on the cytomorphological features, all the cases were subdivided into six groups as follows: Pattern I: Caseous necrosis & epithelioid cell granulomas Pattern II: Caseous necrosis, epithelioid cell granulomas with inflammatory background (lymphocytes / acute inflammatory infiltrate) Pattern III: Non-caseating background& epithelioid cell granulomas Paper ID: ART20183250 DOI: 10.21275/ART20183250 789