P37
Performance evaluation of mfloDx™ MDR-TB: An innovative technology for the detection of Multi Drug Resistant-Tuberculosis
P Rajendran(1) G Ramasubban(2) R Golla(1) S Egambaram(1) S Shanmugam(1) P Chandrasekaran(1) P Asalapuram(2)
1:Department of Bacteriology, ICMR - National Institute for Research in Tuberculosis, Chennai, Tamilnadu, 600031, India; 2:EMPE Diagnostics Private Limited, Hyderabad, Telangana, 500078, India
Purpose: The molecular test, mfloDx™ MDR-TB combines padlock probes-dependent rolling circle amplification technology with sensitive lateral flow biosensors to detect Mycobacterium tuberculosis complex (MTC) and its drug resistance genotypes most common mutations in rpoB, katG and inhA. The ICMR-NIRT evaluated its performance on stored sputum samples from presumptive TB patients.
Methods: A total of 225 sputum smear positive and negative samples were included in this retrospective study. The samples were decontaminated by NaLC-NAOH, heat-lysed and directly tested with mfloDx™ MDR-TB test kits. So far, 104 smear positive and 50 smear negative sputum samples were tested. The Genotype MTBDR plusv2 (LPA) tests are used as the comparator for drug resistance testing.
Results: Clinical sensitivity and specificity of the mfloDx™ MDR-TB for TB detection was 100% with an invalid rate of <1% (99/100) from smear positive samples. All the 50 TB negative sputum samples were negative indicating its 100% specificity. Among the TB positive samples, 49 were sensitive to both RIF and INH, 7 were MDR-TB, 4 were resistant to RIF and 37 were resistant to INH. The mfloDx™ MDR-TB test has shown 100% sensitivity for RIF and INH resistance samples, while 100% specificity for RIF and 98.5% for INH resistance. The indeterminate rate was 1.9% and 5.8% for RIF and INH genotyping, respectively.
Conclusion: The study results implies that mfloDx™ MDR-TB could offer better results compared to LPA in terms of cost effectiveness, turnaround time and ease of use, for M. tuberculosis and its drug resistance detection.