Diagnosis of Tuberculous Lymphadenitis Using Fine Needle Aspiration Cytology: A Comparison Between Cytomorphology and GeneXpert Mycobacterium Tuberculosis Resistant to Rifampicin (MTB/RIF) Test

Abstract

NOTICE: THIS ARTICLE HAS BEEN RETRACTED.

Background: Diagnosis of tuberculous lymphadenitis is challenging. Fine needle aspiration cytology (FNAC) can provide a diagnosis suggestive of tuberculosis (TB) when there are epithelioid cells with/without caseation necrosis. But epithelioid cells can occur in some other conditions as well. Xpert MTB/RIF test, a relatively newer technique, can detect bacteria specific DNA by polymerase chain reaction (PCR) and can also detect rifampicin resistance. This study was undertaken to see the role of Xpert test in the diagnosis of tuberculous lymphadenitis from fine needle aspiration (FNA) material, in comparison to cytomorphological diagnosis.

Methods: It was a cross-sectional study conducted in the Department of Pathology, BSMMU in collaboration with International Centre for Diarrhoeal Disease Research (icddr, b). Study population was clinically suspected cases of tuberculous lymphadenitis patient referred to Pathology Department, BSMMU. Total number of cases is 351. After FNA, cytomorphological diagnosis was done in Pathology Department, Xpert test in Microbiology Department and culture in icddr,b. Results of FNAC and Xpert test were compared. Kappa test was done to calculate percentage of agreement of FNAC and Xpert test with culture.

Results: Final analysis was done in 317 cases following exclusion criteria. Sensitivity, specificity, positive predictive value and negative predictive value of FNAC were 79.7%, 48.1%, 31.9% and 88.6%, respectively. Percentage of agreement of FNAC with culture was 0.183 (Kappa test) implying poor agreement. Sensitivity, specificity, positive predictive value and negative predictive value of Xpert were 95.9%, 60.5%, 42.6% and 98% respectively. Percentage of agreement of Xpert test with culture was 0.39 (Kappa test) implying a slight agreement.

Conclusions: In this study, sensitivity of Xpert was higher than FNAC. It was helpful in detecting TB in suppurative lymphadenitis where granuloma/caseation was not found. Cytomorphology, on the other hand, can diagnose granulomatous as well as reactive and other disease conditions. If facilities permit, both FNAC and Xpert test would better to be done.




Clin Infect Immun. 2019;4(1):6-11
doi: https://doi.org/10.14740/cii77