Assessment of different samples for molecular diagnosis of extra-pulmonary tuberculosis

Extrapulmonary tuberculosis is an important clinical problem particularly in developing countries. The aim of this study was to assess two different samples (blood and fluid) for the diagnosis of extra-pulmonary tuberculosis (abdominal tuberculosis and tuberculous lymphadenitis). The study subjects were recruited from WadMedani Teaching Hospital during 2009-2013. Seventy five ascetic fluid and blood samples were collected from each suspected patient with abdominal tuberculosis and twenty five lymphatic aspirates and blood samples were collected from each suspected tuberculous lymphadenitis patient. DNA was extracted using DNPTM kit (CinnaGenInc) and polymerase chain reaction (PCR) was done using IS6110 gene for both samples. In abdominal tuberculosis, 20/75 (27%) were positive for tuberculosis when ascetic fluid was used and 9/75 (12%) in case of blood samples. The comparison between ascetic fluid and blood samples, showed that, there was a significant difference in both results, P-value < 0.05. In tuberculous lymphadenitis, 13/25 (52%) and 3/25 (12%) were positive to tuberculosis when lymph aspirate and blood were used respectively. This study concluded that the best sample for diagnosis of abdominal TB and lymphadenitis is ascetic fluid and LN aspirate. This study recommends that ascetic fluid and lymph aspirate samples are recommended to be used in molecular diagnostic test.