Comparative evaluation of PCR using IS6110 and a new target in the detection of tuberculous lymphadenitis

We evaluated TRC4 primers using polymerase chain reaction (PCR) which ampli fy a new target sequence from Mycobacterium tuberculosis genome to diagnose tuberculous lymphadenitis and compared the results with PCR using the wide ly used IS6110 primers. The PCR results were also compared with conventiona l methods like smear, culture and, histopathology, The sensitivity of PCR u sing both probes is higher than the conventional methods. Out of 101 sample s analysed (49 fresh and 52 fixed specimens), PCR using IS6110 and TRC4 pri mers was positive in 64 and 70 samples, respectively, whereas results with culture and histopathology methods were positive only in 49 and 58 samples, respectively. The problem of false negativity of IS6110 due to the absence of IS6110 copy in 4 M. tuberculosis isolates was overcome by using TRC4 pr imers. The results indicate that with improvement in PCR techniques, PCR us ing both probes, IS6110 and TRC4 can be a rapid and sensitive adjunct to co nventional techniques in the diagnosis of tuberculous lymphadenitis.