COMPARISON OF ZIEHL-NEELSEN STAINS WITH FINE NEEDLE ASPIRATION TECHNIQUE IN DIAGNOSIS OF TUBERCULOUS LYMPHADENITIS IN A TERTIARY CARE HOSPITAL, SOUTH BIHAR (INDIA).

Corresponding Author:
Dr. Chandan Kumar Poddar,
Research Scholar, Department of Microbiology,
Indira Gandhi Institute of Medical Sciences, Patna.
E-mail: chandan_microbiology@yahoo.co.in

ABSTRACT

BACKGROUND

Tuberculosis continues to be a major health problem in developing countries. Tuberculosis is one of the oldest diseases known to affect humans and is caused by Mycobacterium tuberculosis. Lymphadenopathy is the most common presentation of extrapulmonary tuberculosis. Tuberculous (TB) lymphadenitis is one of the common causes of lymphadenopathy. This study was conducted to compare cytology, ZN staining and culture findings of clinically suspected tuberculous lymphadenitis cases.

MATERIALS AND METHODS

The study design is a descriptive study. Total 220 patients of lymphadenopathy referred to the Department of Pathology, Vardhman Institute of Medical Sciences, Pawapuri, Nalanda, Bihar and Associated Hospital of Bihar between March 2015 and May 2017 were included. FNAC was performed in all these patients and smears were prepared. Smears were stained with haematoxylin and eosin stain. ZN staining for acid-fast bacilli (AFB) was carried out on separate slide. Using solid culture (BACTEC) as the gold standard, we assessed the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa value of the FNAC for detecting MTB and ZN staining for acid-fast bacilli (AFB) respectively.

RESULTS

Maximum number of patients [40% (40/100)] were from age group of 11–30 years. Total 220 cases [55% (55/100) females and 40% (40/100) males] were included in the study. Of 220 cases, 50 (50%) had tuberculosis, 50 (50%) had lymphadenitis other than tuberculosis, and 10 (10%) had malignant lymphadenopathy, including 02 (02%) cases of primary malignancy (i.e. lymphoma) and 9 (09%) cases of metastasis to lymph nodes. The cytology suggestive of tuberculous lymphadenitis was found in 100 (45.45%) cases out of total 220 cases. Ziehl-Neelsen stain demonstrated acid-fast bacilli (AFB) in 40 (18.18 %) cases and BACTEC isolated mycobacteria in 60 (27.27%) cases. When setting the results of Culture (BACTEC) as the gold standard, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa value of the FNAC in the diagnosis of TB lymphadenitis, results were 96.15%, 96.00%, 95.23% and 96.77% and 0.9172 respectively. In addition, when compared with ZN stain in the diagnosis of TB lymphadenitis, the sensitivity, specificity, PPV, NPV and Kappa were 93.33%, 98.88%, 95.45%, 98.34% and 0.928 respectively.

CONCLUSION

FNAC is an assay that has high sensitivities, is optimally selected, efficient, easy to perform, and is an economical test for initial diagnostic workup in patients with TB lymphadenitis. Supplementation of ZN stain with FNAC increases the rates of diagnosis.

KEYWORDS

Tuberculosis, Lymphadenopathy, BACTEC, Fine Needle Aspiration Cytology, Ziehl-Neelsen Stain.