ABBOTT REALTIME MTB RIF/INH RESISTANCE

CE Marked                                                                                                          For In Vitro Diagnostic Use

The Abbott RealTime MTB RIF/INH Resistance assay provides qualitative resistance detection within a single assay for the two most important first-line M. tuberculosis (TB) drugs.

Two MTB Resistance Tests in One Assay

The Abbott RealTime MTB RIF/INH Resistance assay provides:

  • Identification of rifampicin (RIF) resistance and isoniazid (INH) resistance targeting rpoB, katG and inhA upper stream promoter regions in one assay  
  • Sample inactivation procedure minimizes risk of infection during specimen handling  

The Abbott RealTime MTB RIF/INH Resistance assay is an in vitro polymerase chain reaction (PCR) assay for the qualitative detection of Rifampicin (RIF) and Isoniazid (INH) resistance in MTB positive samples. The assay will be used to test specimens of sputum or bronchial alveolar lavage and N-acetyl-L-cysteine (NALC)-prepared sediments prepared from sputum and bronchial alveolar lavage. The assay is intended for use in conjunction with clinical presentation and other laboratory markers for use as an aid in identifying MTB RIF and/or INH resistant MTB strains.

Clinical Sensitivity and Specificity

Performance characteristics of the Abbott RealTime MTB RIF/INH Resistance assay were established by testing 233 MTB positive patient specimens from non-US populations; 138 sputum specimens and 95 N-Acetyl-L-Cysteine (NALC) of sputum specimens. RIF and INH susceptibility were determined by Drug Susceptibility Tests (DST). RIF results were obtained for all three assays (DST, Abbott and the RIF comparator) for 216 specimens. INH results were obtained for all three assays (DST, Abbott and the INH comparator) for 220 specimens. Three MTB INH drug sensitive samples by DST were reported as MTB INH drug resistant in both Abbott RealTime MTB RIF/INH Resistance and the INH comparator and therefore not included in the analysis. DNA sequencing was performed for clinical specimens with discrepant results between Abbott RealTime MTB RIF/INH Resistance and DST test, but was not used to impact the sensitivity and specificity analyses.

Development Philosophy

The Abbott RealTime MTB RIF/INH Resistance assay design had been developed based on Abbott Molecular’s RealTime legacy and commitment to reducing the burden of infectious disease. Abbott RealTime MTB RIF/INH Resistance assay offers the most efficient workflow from low to high volume by mPLUS extended reagent use and introduces a new automated reflex process.

Enabling Solutions

Abbott RealTime MTB RIF/INH Resistance assay offers flexibility, including: 

  • Optional automated reflex of already extracted DNA from MTB-positive specimen to RealTime MTB RIF/INH Resistance. This enables a fully automated workflow, from extraction to amplification and detection. 
  • Optional mPlus extended reagent use allows flexible, low-to-high throughput
ABBOTT REALTIME MTB RIF/INH RESISTANCE 
Clinical sensitivityRifampicin 94.8%; isoniazid 88.3%
Clinical specificityRifampicin 100%; isoniazid 94.3%
Limit of Detection (LoD)60 CFU/mL (probit analysis 32.37 CFU/mL with 95% probability)
Target RegionProbes targeting rpoB for Rifampicin resistance and katG and inhA upper promoter region for Isoniazid resistance
Reported resultsRif R-, Rif R det; INH R-, INH High R, INH Low R (see package insert for further details)
Subspecies coverageEight members of MTB complex
M. tuberculosis, M. africanum, M. bovis, M. bovis BCG, M. microti, M. caprae, M. pinnipedii, M. canetti
Internal controlProcessed with each sample
Specimen typeSputum or bronchial alveolar lavage, or the NALC sediment of sputum or bronchial alveolar lavage, or already extracted DNA of MTB-positive specimens
Input volume0.8 mL of inactivated specimen if extraction is needed, optional use of already extracted DNA of MTB-positive specimen
Sample preparationExtraction: m2000sp or manual
Optional use of automated reflex with m2000sp allows use of already extracted DNA of MTB-positive specimen

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