Use of polymerase chain reaction in the diagnosis of abdominal tuberculosis

Early diagnosis and prompt treatment of abdominal tuberculosis is vitally important as it greatly reduces disease and treatment related morbidity and even mortality in extreme cases. A polymerase chain reaction (PCR) test was evaluated for its feasibility as a diagnostic tool in abdominal tuberculosis (TB) in the Indian scenario.

PCR for the identification of M. tuberculosis amplified a 340 bp nucleotide sequence located within the 38 kDa protein gene of M. tuberculosis. Tissues for processing were obtained from patients suspected to have abdominal TB. These were from various sources such as abdominal lymph nodes, segments of intestine and bowel obtained at various times and in different ways such as laparoscopy, colectomy, bowel and lymph node resection. Fifty such patients had their tissues sent for PCR.

PCR results were compared with histopathology (HP). Of the 50 samples, 31 were positive for abdominal TB by HP whereas 30 were positive by PCR. Twenty-four of these were positive for both HP and PCR while of the seven samples positive for HP, five were negative and two gave inhibition by PCR. Six samples negative by HP were positive by PCR.

This study demonstrates that PCR can be used as an effective tool to diagnose abdominal TB.