Background: Tuberculosis has emerged as one of the most lethal diseases man has ever faced. India accounts for nearly one third of global burden of tuberculosis. Tubercular lymphadenitis is the most common type of extra pulmonary tuberculosis. This study was done to assess the diagnostic significance of serum adenosine deaminase levels in FNAC confirmed cases of tuberculous lymphadenitis and to determine its sensitivity and specificity; and to rule out early tuberculosis in cases reported by FNAC as reactive lymphadenitis. Methods: A two year prospective study of 35 cases presenting with lymphadenitis from October 2010 to October 2012 was done. The study subjects were first confirmed by fine needle aspiration cytology and AFB staining. This was followed by the measurement of serum adenosine deaminase levels. Results: The mean age of the patients in the present study was 28 years with no significant difference in the gender distribution. Under reactive lymphadenitis, abscess, and suppurative lymphadenitis groups, reactive lymphadenitis was more common with 60% of cases. Under granulomatous lymphadenitis group, granulomatous lymphadenitis was more common with 80% of cases. Numbers of granulomas/20 HPF were significantly more associated with Tubercular lymphadenitis with p=0.008**. Number of giant cells /20 HPF were statistically similar in two groups with P=1.000. The most common significant range of serum adenosine deaminase levels was 31 to 40 U/L. Conclusion: Serum adenosine deaminase levels are an adjunct to FNAC in the diagnosis of tuberculous lymphadenitis. As the number of granulomas increase, the serum adenosine deaminase levels also increases.
