Evaluation of Discrepancy between GeneXpert (MTB/RIF) Assay and Drug-Susceptibility Test Result

Abstract

Erlina Burhan, Gassani Amalia, Darayu Calvert Wilson

Rationale. Discrepancies between tests for drug-resistant tuberculosis infections are becoming more common as diagnostic tools become more varied. These discrepancies may partly causes the longer time to diagnose tuberculosis that leads to delay of treatment. Objectives. The main objective was to investigate discrepancies between GeneXpert (MTB/RIF) and drug-susceptibility test in diagnosing tuberculosis drug resistance and which factors were associated with those discrepancies. Other purpose was to measure the proportion of different types of drug-resistant tuberculosis and to identify the factors affecting the occurrence of multi-drug resistant tuberculosis in Indonesia. Methods. This was a cross-sectional study. Demographic data and clinical characteristics of patients were collected from eTB Manager of Persahabatan General Hospital from January 2015 to December 2017. We did descriptive analysis of patient characteristics, resistance pattern, and treatment outcomes. Association of patient characteristics with tests discrepancies and occurrence of multi-drug resistant tuberculosis were further analyzed. Measurements and Main Results. Discrepancy of GeneXpert (MTB/RIF) and drug-susceptibility test were found in 48 cases (7%). Factors that significantly influenced the emergence of a discrepancy were number of previous treatments (p=0.009) and use of different sputum samples (p<0.001). Multi-drug resistant was the most prevalent type of drug resistance (35%, N=239) and was affected significantly by re-treatment cases. Conclusions. The number of discrepancies between GeneXpert (MTB/RIF) and drug-susceptibility test was low and associated with the number of previous treatments and use of different sputum samples. Adherence to diagnosis and treatment protocol should be done to reduce tests discrepancies and re-treatment possibilities.