# A comparative study of MassARRAY and GeneXpert assay in detecting rifampicin resistance in tuberculosis patients’ clinical specimens

## TL;DR

This study compares two methods for detecting rifampicin resistance in tuberculosis and finds that MassARRAY is more reliable than GeneXpert.

## Contribution

The study provides new evidence on the reliability of MassARRAY for rifampicin resistance detection compared to GeneXpert.

## Key findings

- MassARRAY showed higher sensitivity than GeneXpert in TB diagnosis.
- Concordance in detecting rifampicin resistance was 90% between MassARRAY and Xpert assay.
- MassARRAY demonstrated 87.9% consistency in identifying multiple drug resistance.

## Abstract

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a potent tool for detecting drug resistance in tuberculosis (TB); however, concerns about its reliability have been raised. In this study, we assessed the reliability of MassARRAY (Sequenom, Inc.), which is a MALDI-TOF MS-based method, by comparing it to the well-established GeneXpert assay (Cepheid) as a reference method.

A retrospective study was conducted using laboratory data retrieved from Henan Chest Hospital (Zhengzhou, China). To ensure a rigorous evaluation, we adopted a comprehensive assessment approach by integrating multiple outcomes of the Xpert assay across various specimen types.

Among the 170 enrolled TB cases, MassARRAY demonstrated significantly higher sensitivity (85.88%, 146 of 170) compared to the Xpert assay (76.62%, 118 of 154) in TB diagnosis (p < 0.05). The concordance in detecting rifampicin resistance between MassARRAY and the combined outcomes of the Xpert assay was 90%, while it was 97.37% (37 of 38) among smear-positive cases and 89.06% (57 of 64) among culture-positive cases. When compared to the phenotypic susceptibility outcomes of the 12 included drugs, consistency rates of 81.8 to 93.9% were obtained, with 87.9% for multiple drug resistance (MDR) identification.

MassARRAY demonstrates high reliability in detecting rifampicin resistance, and these findings may offer a reasonable basis for extrapolation to other drugs included in the test panel.