Abstract
Background: Although tuberculosis is a known disease, still on occasion, the tuberculosis patients remain
undiagnosed and hence not treated appropriately. In some cases, the patient is not able to give a proper
sputum sample. In some other cases, expert laboratory technician to examine the patient’s sputum smear is
not available. Furthermore, and in most cases of extrapulmonary tuberculosis, invasive diagnostic procedures
such as biopsy might be followed. The aim of this study was to investigate the diagnostic value of serum level
of adenosine deaminase (ADA) in extra pulmonary tuberculosis.
Methods: In this analytical study, pulmonary tuberculosis patients were compared with two other groups of
patients including lung cancer patients and healthy controls, based on national tuberculosis protocol. In each
group, 40 patients who almost matched for age and sex were included. Blood samples were taken from the
participants to measure serum ADA levels. Data were analyzed using SPSS software version 15.0.
Results: Based on the data analyzed in this study, the mean ADA level in the patients with extra pulmonary
tuberculosis was 23.8 IU/L which was significantly higher than that in the other groups (P<0.001). Mean ADA
levels in lung cancer patients and in healthy subjects were 15.8 IU/L and 10.7 IU/L, respectively.
Conclusions: According to the results of this study, higher cut-off value for ADA would increase the specificity
up to 100%. Moreover, serum ADA level can be a valuable additional index in diagnosis of extra pulmonary
tuberculosis.