Abstract:

Objective: To evaluate the diagnostic value of GeneXpert MTB/RIF (Xpert) detection of stool samples in patients with intestinal tuberculosis. Methods: The laboratory data of stool specimens from 98 patients with suspected intestinal tuberculosis admitted to Shaanxi Provincial Hospital of Tuberculosis Prevention and Treatment from August 2019 to May 2022 were retrospectively analyzed, which included test data detected by concentrated collection of bacteria floating method (referred to as “collection method”), BACTEC MGIT 960 liquid culture (referred to as “MGIT 960 culture”) and Xpert method simultaneously. Taking the final clinical diagnosis as the reference standard, the diagnostic efficacy of the three methods for detecting fecal specimens for intestinal tuberculosis was evaluated. Results: Of the 98 patients with suspected intestinal tuberculosis, 54 (55.1%) patients were confirmed intestinal tuberculosis, and 44 (44.9%) were non-intestinal tuberculosis. The positive detection rates of bacterial Xpert method (38.8% (38/98)) was apparently higher than collection method (15.3% (15/98)) and MGIT 960 culture (16.3% (16/98)), respectively. The differences were all statistically significant (χ²=25.496, P=0.000; χ²=20.224, P=0.000). The positive detection rate of stool samples positive for smear and/or culture was 95.5% (21/22), and the positive detection rate of stool samples negative for both smear and culture was 53.1% (17/32). Taking clinical diagnosis as reference, the sensitivity of collection method, MGIT 960 culture and Xpert method were 27.8% (15/54), 29.6% (16/54) and 70.4% (38/54), respectively, and the specificity was 97.7% (43/44), 100.0% (44/44) and 90.9% (40/44), the coincidence rates were 59.2% (58/98), 61.2% (60/98) and 79.6% (78/98), respectively, the Kappa values were 0.24, 0.27, and 0.60, respectively. Conclusion: The sensitivity and Kappa values of Xpert method for detecting feces are higher than that of collection method and MGIT 960 culture, which is consistent with clinical diagnosis. Xpert method can provide a diagnostic basis for early diagnosis of intestinal tuberculosis.

Key words: Intestinal tuberculosis, Feces, Molecular diagnostic techniques, Diagnostic, Comparative studies