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摘要
Background: The diagnostic value of GenoType MTBDRplus assay hasn't been validated in smear-negative retreated tuberculosis (TB) patients. Therefore, a retrospective study was conducted to evaluate it. Methods: Between Jun, 2013 and Sep, 2016, 35 retreatment TB patients were enrolled in the study. The phenotypic drug susceptibility test (DST) was evaluated using indirect proportion method with L-J medium. The GenoType MTBDRplus assay was done on culture specimens according to the manufacturer's instructions. The sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of GenoType MTBDRplus assay in detection of isoniazid (INH)and rifampicin (RIF)-resistance were calculated using the phenotypic DST assay as the gold standard. Results: The average age was 28.9 +/- 11.3 years (range 5 to 61 years), 57.1% (21/35) were male. For detecting INH-resistance, the sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of GenoType MTBDRplus assay were 94.1% (73.0%, 99.0%), 55.6% (33.7%, 75.4%), 2.12 (1.25, 3.60) and 0.106 (0.02, 0.74), respectively; For detecting RIF-resistance, the sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were 100% (85.1%, 100.0%), 91.7% (64.6%, 98.5%), 12.00 (1.84, 78.37) and 0, respectively; For detecting MDR-TB, the sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were 93.3% (70.2%, 98.8%), 65.0% (43.3%, 81.9%), 2.67 (1.45, 4.92) and 0.10 (0.02, 0.70), respectively. Conclusion: The GenoType MTBDRplus assay has high sensitivity for detection of INH-and RIF-resistance in retreatment TB patients. However, the specificity is moderate, this should be taken into account when interpreting the test results.
