Diagnostic performance of Xpert MTB/RIF Ultra assay for tuberculosis in stool specimens among adult presumptive TB patients in a generalized HIV epidemic setting
The Xpert-Ultra assay in stool specimens shows high sensitivity and specificity for diagnosing TB in patients who cannot produce sputum, but further research is needed to validate these findings.
Where it sits
this study against the rest of the ss-31 corpusSummary and findings
The study evaluated the diagnostic performance of the Xpert MTB/RIF Ultra assay in stool specimens among adult presumptive TB patients in a generalized HIV epidemic setting. A total of 113 participants were included, with 31 confirmed TB cases. The sensitivity of the Xpert-Ultra assay in stool was 90.32%, and specificity was 98.78%.
Abstract
BACKGROUND Diagnosis of Tuberculosis (TB) from stool specimen using the Xpert MTB/RIF Ultra assay (Xpert-Ultra assay) is important to confirm diagnosis for presumptive TB patients who are unable to produce sputum. We evaluated diagnostic performance of the Xpert-Ultra assay in stool specimen among adult migrant population living in generalized HIV epidemic situation. METHODS A prospective, cross-sectional study was conducted at outpatient and inpatient departments of the Shoklo Malaria Research Unit (SMRU) clinics and Mae Tao Clinic (MTC) located in Thailand-Myanmar border area. Presumptive TB patients of any age who were registered between November 14, 2022, and May 23, 2023, were eligible for inclusion based on reported signs and symptoms and/or radiological findings. Using liquid MTB culture in sputum as reference standard, evaluation of diagnostic performance of the Xpert-Ultra assay in stool was performed, and it was also compared with performance of smear microscopy and Xpert-Ultra assay in sputum specimen. RESULTS Total 113 participants were included in the analysis; 9 (7.96 %) had human immunodeficiency virus (HIV) infection, and 31 (27.43%) had confirmed TB on culture results. Among these culture-confirmed TB cases, the sensitivity of Xpert-Ultra assay in stool specimen was 90.32 % (95% confidence interval [CI], 74.25% to 97.96%). Although the absolute difference in sensitivity of Xpert-Ultra assay in stool was 3.23 % lower than sputum (95% CI: -9.46 % to 3.00 %), there was no statistically significant difference between the two sample types. The specificity of Xpert-Ultra assay in stool specimen was 98.78% (95% CI, 93.39% to 99.97%) against culture-negative TB cases, giving an absolute difference of 1.22 % (95% CI, -1.16% to 3.59%) compared to sputum Xpert-Ultra assay. This method demonstrated that diagnostic performance was consistent with World Health Organization (WHO) target product profiles on low-complexity assays for detecting Mycobacterium tuberculosis (MTB). CONCLUSIONS The Xpert-Ultra assay in stool specimen can be considered as a potential, alternative method in diagnosis of presumptive pulmonary TB in adults when respiratory sample is difficult to collect.
Background
The study appears to address the diagnostic performance of the Xpert MTB/RIF Ultra assay for detecting tuberculosis in stool specimens. This is relevant in settings with high HIV prevalence, where TB diagnosis can be challenging. The study's focus on stool specimens may offer a non-invasive diagnostic alternative.
Methods
Not reported in abstract.
Results
Not reported in abstract.
Interpretation
Not reported in abstract.
Key findings
- Not reported in abstract.
Limitations
- Not reported in abstract.