female lab worker with molecular nodes

An effective MRSA/SA screening program uses rapid techniques

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Method sensitivity and time-to-result are critical factors contributing to the success of a screening program for Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA) infections. Time delays associated with incubation of conventional culture-based methods can delay implementation of infection control measures, requiring more general infection control measures to be used for all patients, providing opportunities for transmission. Active surveillance to identify MRSA/SA carriers is helping to mitigate the potential consequences of disease, providing relief to patients and health care institutions facing the challenges of escalating costs. 2 

Only rapid techniques, such as the cobas MRSA/SA Test, enable early detection of MRSA and SA in colonized patients leading to rapid implementation of appropriate barrier precautions. The test offers microbiology labs an innovative assay that detects both organisms from a single nasal swab specimen, providing time-saving efficiencies through primary sample vial loading for lifesaving answers.

The cobas MRSA/SA Test detects both targets to deliver high quality results

Performance of the cobas MRSA/SA Test compared to direct and enrichment culture 4

Exceptional performance for effective MRSA surveillance

The cobas MRSA/SA Test is a fast, effective, and efficient way to test for both MRSA and SA in patient samples.

The cobas MRSA/SA Test:

  • Quickly identifies colonized patients to enable decisive action
  • Provides the sensitivity and specificity that only polymerase chain reaction (PCR) technology can deliver3
  • Simplifies data interpretation with patented, state-of-the-art software algorithms
  • Adds to the expanded test menu on the cobas® 4800 System, which also includes Clostridium difficile (C. difficile) testing 

Get the sensitivity and specificity that only PCR can offer

The performance of the cobas MRSA/SA Test compared to the combination of direct and enrichment culture from 2500 evaluable results from MRSA, and from 2501 evaluable results for SA is shown below:

MRSA: Direct and Enrichment Culture 4
Sensitivity 93.1%
Specificity 97.5%
Positive Predictive Value 71.6%
Negative Predictive Value 99.5%
SA: Direct and Enrichment Culture 4
Sensitivity 93.9%
Specificity 94.2%
Positive Predictive Value 85.3%
Negative Predictive Value 97.7%

The performance of cobas MRSA/SA Test compared to initial direct culture demonstrated the following positive percent agreement and negative percent agreement:

MRSA: Direct Culture 4
Positive Percentage Agreement 97.1%
Negative Percentage Agreement 96.9%
SA: Direct Culture 4
Positive Percentage Agreement 97.0%
Negative Percentage Agreement 92.1%

Deliver high-quality results in a matter of hours with the cobas MRSA/SA Test

Less hands-on time means more walk-away time and reduced chance of error

The cobas MRSA/SA Test saves time with first-of-its-kind primary vial loading. Using the MSwab™ system, specimens collected on a FLOQSwab™ are transferred directly into the primary vial for testing. The MSwab system is optimized for molecular and culture applications. 

Labs can run 4 to 5 small runs or 2 high-volume runs for up to 188 results/ 8 hours.


Run specimens with automated efficiency

Running on the cobas 4800 System, the cobas MRSA/SA Test can process specimens using one of the fastest, most advanced real-time PCR amplification and detection methods available today. The cobas MRSA/SA Test requires up to 93% less hands-on time compared to other molecular tests for 94 samples.1

93% less total hands-on time3

MRSA Hands-on Time

Run mixed batch assayscobas-4800-system-mixed-batch-testing-screen.png

The cobas 4800 System offers flexibility with parallel sample processing capabilities. cobas MRSA/SA Test samples can be run with different tests and sample types in one run. 

Run mixed batch assays of: 

  • Nasal (cobas MRSA/SA Test) 
  • Stool (cobas®  Cdiff Test) 
  • Anogenital lesions (cobas® HSV 1 and 2 Test)
In addition to parallel sample processing, the cobas 4800 System offers an expanding test menu. 
cobas MRSA/SA Assay Performance and Specifications 4
Sample Type Copan MSwab Collection, Transport and Preservation System
Sample Processing Primary vial loading with MSwab System directly on the cobas 4800 System
Sample Versatility Molecular or culture capability
Contamination Control AmpErase Enzyme
PCR Target Region MRSA: SCCmec right-extremity junction
MSSA: capsular polysaccharide enzyme (CPE) gene
SCCmec Coverage I, II, III, IV, IVa, V, VI, VIII
Clinical Sensitivity* MRSA: 93.1%
SA: 93.9%
Clinical Specificity* MRSA: 97.5%
SA: 94.2%
Workflow Mixed batch capability; up to 4-5 small runs or 2 high-volume runs for up to 188 results/ 8 hours
*Compared with direct culture cytotoxicity test

Intended Use: The cobas MRSA/SA Test on the cobas 4800 System is an automated, qualitative, in vitro diagnostic test, that utilizes real-time polymerase chain reaction (PCR), for the direct detection of methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus (SA) DNA from nasal swabs to aid in the prevention and control of MRSA and SA infections in healthcare settings. The cobas MRSA/SA Test is not intended to diagnose, guide or monitor treatment for MRSA or SA infections, or provide results of susceptibility to methicillin. Concomitant cultures are necessary only to recover organisms for epidemiology typing or for further susceptibility testing.



  1. Argent Microbiology Workflow Study 2014. Roche data on file.
  2. Peterson LR. J. Clin. Microbiol.-2010-POINT-683-6
  3. Peterson LR et al. J. Clin. Microbiol. 2010. 1661-6
  4. cobas®MRSA/SA [package insert]. Indianapolis, IN: Roche Diagnostics; 2015.