Karius Spectrum AMR Detection
Drug-resistant infections threaten millions of people each year, including hospitalized and other high-risk patients.
>2.8M people are sickened by drug-resistant infections annually in the United States, with 35,000 deaths1
~70% of pathogens causing bacterial infection in hospitals are resistant to at least one prevalently used antibiotic in the United States2
~27% of pathogens causing infections after chemotherapy are estimated to be resistant to standard prophylactic antibiotics in the United States3
Ability to target therapy is often limited by culture-dependent methods with low yield in hospitalized patients.4
Karius Spectrum AMR Detection Capabilities
The Karius SpectrumTM test, a minimally invasive liquid biopsy for infectious diseases, is the first commercially available plasma based, culture-independent test with AMR marker detection, designed to help clinicians use targeted therapy to help improve patient outcomes. AMR capabilities include detection of antimicrobial resistance for 18 bacterial pathogens and 4 classes of antimicrobial resistance:
- Methicillin-resistant Staphylococci (SCCmec, mecA, mecC)
- Vancomycin-resistant Enterococci (vanA, vanB)
- Carbapenem-resistant Gram-negative bacteria (KPC)
- Extended spectrum beta-lactamase (ESBL)-producing Gram-negative bacteria (CTX-M)
AMR Clinical Validation Performance
PPA = Positive Percent Agreement
NPA = Negative Percent Agreement
Total Validation Yield = Calculated by sum of presence and absence calls for an AMR marker, divided by the sum of all microbes in that drug class category that could have those markers
a. No mecC, vanB, or blaKPC positive calls were detected.
b. SCCmec and mecA combined in reporting.
c. 54 gram-negative detections had blaCTX-M phenotype; 52 had blaKPC phenotype. After blaCTX-M discrepancy resolution (LB-75775 → TN): PPA 66.7% (6/9) [29.9–92.5%] · NPA 97.2% (35/36) [85.5–99.9%] · Accuracy 91.1% (41/45) [78.8–97.5%]
&Clinical validation performance may differ from what is seen in production because metrics may be study-dependent.
Supporting validation data is available on file. For more information, please contact help@kariusdx.com
Test Reporting
Species identification and AMR results are typically reported within 24–48 hours of specimen receipt. For eligible specimens, up to 1 in 5 AMR results may be available same-day; remaining results follow within 24 hours as further analysis is completed. The test report will clearly indicate whether the results are final or AMR testing is still in progress. Results are intended to guide antimicrobial management within appropriate clinical context.
*>85% of specimens received by 8:30 AM (PT) Monday through Saturday are reported the next day. Eligible AMR marker results may also be provided at this time; indeterminate results will undergo follow-on testing.
**If specimen volume is sufficient for testing and additional analytical conditions are met.
***Follow-on AMR testing of Karius Spectrum test reported on Sunday would have AMR marker detection addended on Tuesday
For more information about how Karius Spectrum test results are reported, visit For in-depth information about AMR product performance, download AMR Technical Sheet.
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References
- CDC: https://www.cdc.gov/drugresistance/biggest-threats.html
- FDA: https://www.fda.gov/drugs/information-consumers-and-patients-drugs/battle-bugs-fighting-antibiotic-resistance.
- Teillant, A et al. Lancet Infect Dis. 2015 Dec;15(12):1429-37. Epub 2015 Oct 22.
- Weinstein MP, et al. Laboratory Detection of Bacteremia and Fungemia, p.28. In: Carroll KC, Pfaller MA. Manual of Clinical Microbiology, 2019.