ABSTRACT
Tuberculosis is one of the major health problems in developing countries like India. Even though lungs are the commonly involved organs in Tuberculosis, extrapulmonary presentations are on the rise nowadays. Among the various types of presentations of extrapulmonary tuberculosis, lymphadenitis is the most common presentation. A spectrum of investigations is available for diagnosis, and molecular methods like CBNAAT and PCR analysis are highly reliable. But their disadvantage is their cost and requirement of trained personnel. FNA is the first line of investigation but is lacking in sensitivity and culture method is time consuming. So, Modified Ziehl Neelsen method with low cost and less time may be considered as an alternative. We wanted to evaluate the sensitivity of the Modified Bleach Ziehl Neelsen method and compare the Modified and Conventional Ziehl Neelsen Method in association with the CBNAAT in the diagnosis of TB lymphadenitis.METHODSDiagnostic validation study was conducted with 30 clinically suspected cases of tuberculosis. FNA was done and aspirated material was spread on 2 slides. Slides were stained with H & E stain and convention Ziehl Neelsen stain. Part of the aspirate material was centrifuged with 5 % sodium hypochlorite. Sediment was smeared on a slide and stained with Ziehl Neelsen stain. Remaining material was subjected to CBNAAT assay.RESULTSCorrelation shows that 9, 6, and 11 out of 30 cases were positive for tuberculosis in Conventional, Modified and CBNAAT methods respectively. Sensitivity was 81.81 %; specificity was 94.74%, positive predictive value was 90% and negative predictive value was 90% for Conventional Ziehl Neelsen Method and 54.55%, 94.73%, 85.71% and 78.26%, respectively for modified bleach method.CONCLUSIONSConventional method is found to be more sensitive than modified method. CBNAAT negative results do not rule out TB. So, they should be correlated with cytology and microbiological studies.