Clinical evaluation of polymerase chain reaction in the diagnosis of joint tuberculosis by detecting DNA of Mycobacterium tuberculosis

Objective To study the role of(polymerase chain reaction PCR)technique in detection of(deoxyribonucleic acid DNA)of Mycobacterium tuberculosis in the samples from joint tuberculosis,and to appraise its clinical value in diagnosis of joint tuberculosis.Methods PCR technique was used to detect blindly DNA of Mycobacterium tuberculosis in 20 standard specimens(5 specimens of Mycobacterium tuberculosis,5 BCG,and 10 other bacteria.)Then,it was used respectively to detect DNA of Mycobacterium tuberculosis in specimens obtained from 95 patients with joint tuberculosis and 98 ones with non-tubercular joint disorders.The clinical evaluation was preformed according to evaluation principle on diagnosis methods based on clinical epidemiology.Results(1)In detection of the standard samples,both Mycobacterium tuberculosis and BCG showed positive,and all the other bacteria negative.(2)In 95 cases of joint tuberculosis,PCR was positive in 78 and negative in 17.In 98 cases of non-tubercular joint disorders,9 cases showed positive,and the others negative.In aspect of detecting DNA of Mycobacterium tuberculosis in specimens of joint tuberculosis,sensitivity of PCR technique was 82.11%,specificity was 90.81%,accuracy was 86.60%,positive predictive value was 89.80%,and negative predictive value was 84.00%.(3)The whole process of PCR amplification was automatic and could be finished within 3 to 6 hours.Conclusions PCR technique is a sensitive,specific,rapid,simple,minimal invasive and sample-microcrystalline method for detection of Mycobacterium tuberculosis in the samples from joint tuberculosis,and it plays a very important role in the early and rapid diagnosis and differential diagnosis of joint tuberculosis.