z-logo
open-access-imgOpen Access
Performance Comparison of GeneXpert MTB/RIF and ProbeTec ET Tests for Rapid Molecular Diagnosis of Extrapulmonary Tuberculosis in a Low TB/MDR-TB Incidence Country
Author(s) -
Mokaddas Eiman,
Ahmad Suhail,
Eldeen Hanaa
Publication year - 2021
Publication title -
medical principles and practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.426
H-Index - 45
eISSN - 1423-0151
pISSN - 1011-7571
DOI - 10.1159/000515254
Subject(s) - original paper
Objective: This study evaluated the performance of GeneXpert MTB/RIF (Xpert) and ProbeTec ET (PTec-ET) assays in diagnosing extrapulmonary tuberculosis (EPTB) in Kuwait. Materials and Methods: We tested nonrespiratory clinical specimens ( n = 3,995) collected from 3,995 patients suspected to have EPTB. These included cavitary fluids ( n = 2,054), fine-needle aspirate (FNA)/pus/tissue biopsy ( n = 1,461), urine ( n = 302), cerebrospinal fluid (CSF, n = 118), and others ( n = 60). All specimens were processed for acid-fast bacilli (AFB), culture in mycobacteria growth indicator tube 960 system, and nucleic acid detection by Xpert and PTec-ET according to manufacturer’s instructions. Results: Of 3,995 specimens, 95 were AFB-positive, 403 were culture-positive, and an additional 86 samples had histopathology suggestive of TB. Using culture as reference, the sensitivity and specificity values were 88.33 and 97.3% for Xpert and 72.95 and 97.80% for PTec-ET, respectively. Although performance of both tests was comparable in AFB-positive samples, Xpert detected significantly more cases in culture-positive samples. Among culture-negative samples, Xpert detected 18 more cases including 16 with histopathological evidence of TB. Lowest positivity was detected for both tests in cavitary fluids. Xpert performed better than PTec-ET in culture-positive FNA/pus/tissue biopsy and CSF samples. Conclusions: Although performance of both tests was suboptimal for AFB-negative/culture-positive samples, Xpert performed better than PTec-ET and also detected more cases of AFB-negative/culture-negative/histopathology-positive samples. PTec-ET was positive in 3, while Xpert was positive in all 6 culture-positive CSF specimens for rapid diagnosis of TB meningitis. Xpert was thus superior to PTec-ET or smear microscopy in rapid diagnosis of EPTB.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here