ABSTRACT
<p><b>BACKGROUND</b>Interferon-gamma release assay (IGRA) has been used in latent tuberculosis (TB) infection and TB diagnosis, but the results from different high TB-endemic countries are different. The aim of this study was to investigate the value of IGRA in the diagnosis of active pulmonary TB (PTB) in China.</p><p><b>METHODS</b>We conducted a large-scale retrospective multicenter investigation to further evaluate the role of IGRA in the diagnosis of active PTB in high TB-epidemic populations and the factors affecting the performance of the assay. All patients who underwent valid T-SPOT.TB assays from December 2012 to November 2015 in six large-scale specialized TB hospitals in China and met the study criteria were retrospectively evaluated. Patients were divided into three groups: Group 1, sputum culture-positive PTB patients, confirmed by positive Mycobacterium tuberculosis sputum culture; Group 2, sputum culture-negative PTB patients; and Group 3, non-TB respiratory diseases. The medical records of all patients were collected. Chi-square tests and Fisher's exact test were used to compare categorical data. Multivariable logistic analyses were performed to evaluate the relationship between the results of T-SPOT in TB patients and other factors.</p><p><b>RESULTS</b>A total of 3082 patients for whom complete information was available were included in the investigation, including 905 sputum culture-positive PTB cases, 914 sputum culture-negative PTB cases, and 1263 non-TB respiratory disease cases. The positive rate of T-SPOT.TB was 93.3% in the culture-positive PTB group and 86.1% in the culture-negative PTB group. In the non-PTB group, the positive rate of T-SPOT.TB was 43.6%. The positive rate of T-SPOT.TB in the culture-positive PTB group was significantly higher than that in the culture-negative PTB group (χ2 = 25.118, P < 0.01), which in turn was significantly higher than that in the non-TB group (χ2 = 566.116, P < 0.01). The overall results were as follows: sensitivity, 89.7%; specificity, 56.37%; positive predictive value, 74.75%; negative predictive value, 79.11%; and accuracy, 76.02%.</p><p><b>CONCLUSIONS</b>High false-positive rates of T-SPOT.TB assays in the non-TB group limit the usefulness as a single test to diagnose active TB in China. We highly recommend that IGRAs not be used for the diagnosis of active TB in high-burden TB settings.</p>
ABSTRACT
@#Objective To investigate the value of real-time fluorescence detection technique of RNA (SAT) constantamplification in monitoring the effect of chemotherapy on patients with sputum positive pulmonary tuberculosis. Methods Sixty-two patients were selected, who were clinically diagnosed as the first-time retreatment for sputum smear-positive pulmonary tuberculosis and were hospitalized in our department from June 2015 to December 2016. After two-month standard anti-tuberculosis treatment, sputum samples were detected by Peng’s vessel acid-fast staining, BACTEC MGIT- 960 culture and strain identification, SAT detection. The BACTEC MGIT-960 culture and strain identification were used as gold standards, the value of SAT during the monitoring the therapeutic effect of the anti-tuberculosis drugs was assessed. Results After the treatment, 49 cases out of 62 showed positive results in mycobacterium tuberculosis culture test, among them 42 patients were diagnosed as human type mycobacterium tuberculosis, 7 patients were diagnosed as nontuberculous mycobacteria infection, and 13 cases showed negative results in mycobacterium tuberculosis culture. Thirty-two cases showed positive results in sputum Peng’s vessel acid-fast staining test, and 30 cases showed negative results. Forty-one cases showed positive results in SAT test and 21 cases showed negative results in SAT. SAT results were well concordant with sputum culture results (Kappa value=0.964), and the sensitivity, the specificity, the positive predictive value and the negative predictive value of SAT were 97.62%, 100%, 100% and 95.24% respectively. Peng’s vessel acid-fast staining results were badly concordant with MGIT-960 culture results (Kappa value=0.086), and the sensitivity, the specificity, the positive predictive value and the negative predictive value of Peng’s vessel acid-fast staining were 54.76%, 55.00%, 71.88% and 36.67% respectively. Conclusion SAT results can be used as good indices during the monitoring therapeutic effects of drugs used for the first-time retreatment in patients with sputum smear-positive pulmonary tuberculosis, which is worth promoting.