Abstract:

Objective To evaluate the diagnostic performance of GeneXpert MTB/RIF (“Xpert”) for tuberculous pleurisy.Methods Pleural effusion samples collected with ultrasound guidance from 180 patients with suspected tuberculous pleurisy from Anshan Tuberculosis Hospital between January 2017 and December 2017 were tested with smear acid-fast bacilli testing (“smear”), liquid culture by BACTEC MGIT 960(“MGIT 960”) and GeneXpert. With clinical diagnosis results as the reference standard, sensitivity, specificity, positive prediction value, negative prediction value and consistent rate were evaluated for performances of smear test, MGIT 960 and GeneXpert test on detecting Mycobacterium tuberculosis (MTB) in those pleural effusion samples.Results Among those 180 suspected patients, 162 cases (90.00%) were confirmed as tuberculous pleurisy (TBP), 18 cases (10.00%) were excluded of TBP. Among the 162 cases of TBP, 61 cases (37.65%) were MGIT 960 culture-positive, 101 cases (62.35%) were diagnosed as TBP basing on standard clinical diagnosis criteria, including clinical symptoms, biochemical indicators of pleural effusion samples, results of chest imaging examination, and diagnostic anti-TB treatment results. Eighteen cases excluded of TBP had lung cancer pleural metastasis in 9 cases, sarcoidosis in 1 case, systematic lupus pleurisy in 1 case, pleural mesothelioma in 2 cases, nephropathy in 2 cases, cardiac insufficiency in 2 cases and hypoproteinemia in 1 case. With clinical diagnosis as the reference standard, the sensitivity of smear test, MGIT 960 and GeneXpert test were 0.00% (0/162), 37.65% (61/162) and 54.94% (89/162) separately; The specificity of three tests were all 100.00% (18/18); Positive prediction value of three tests were 0.00% (0/0),100.00% (61/61) and 100.00% (89/89); Negative prediction value of three tests were 10.00% (18/180),15.13% (18/119) and 19.78% (18/91);Consistent rate of three tests with clinical diagnosis results were 10.00% (18/180), 43.89% (79/180) and 59.44% (107/180) separately. Sensitivity of GeneXpert test was significantly higher than that of the smear and MGIT 960 culture (χ ²=119.82,P=0.000). Conclusion GeneXpert has high diagnostive value in detecting tuberculous pleurisy.

Key words: Tuberculosis,pleural, Pleural effusion, Nucleic acid amplification techniques, Laboratory techniques and procedures, Comparative study