Test ID: CARNP Carbapenemase Detection-Carba NP Test, Varies

Reporting Name
Carbapenemase-Carba NP TestUseful For
Confirmation of carbapenemase production from pure isolates of Enterobacteriaceae or Pseudomonas aeruginosa
Clinical Information
Gram-negative bacilli (GNB) with acquired carbapenemases have disseminated worldwide, rendering them a global threat. The therapeutic armamentarium for infections caused by carbapenem-resistant Enterobacteriaceae (CRE) is limited, and CRE infections have been associated with significant mortality. Enterobacteriaceae harboring Klebsiella pneumoniae carbapenemase are endemic in some regions of the United States, and although still sporadic, GNB harboring New Delhi metallo-beta-lactamase have been reported from several states. Timely detection of these carbapenemases (along with emerging carbapenemases such as OXA-48 and VIM) is important. Detection is challenging since isolates may have only borderline reductions in susceptibility to carbapenems, and carbapenem resistance may be mediated by mechanisms other than carbapenemases (eg, AmpC or extended-spectrum beta-lactamase with decreased membrane permeability). While molecular methods are confirmatory, testing may not be immediately available and may be limited by the number of targets assayed. The modified Hodge test suffers from lack of specificity, a long turnaround time, and poor sensitivity for metallo-beta-lactamase detection. The Carba NP test is preferred over the modified Hodge test due to improved specificity and faster turnaround time.
The Carba NP test is more specific than and as sensitive as the carbapenemase-modified Hodge test. If an isolate is suspected to possess KPC or NDM carbapenemase (eg, due to local epidemiology), KPC and NDM PCR (KPNRP / KPC (blaKPC) and NDM (blaNDM) in Gram-Negative Bacilli, Molecular Detection, PCR) may be preferred over the Carba NP test.
Interpretation
A positive result indicates production of a carbapenemase by the isolate submitted for testing. A negative result indicates lack of production of a carbapenemase by the isolate submitted for testing.
Report Available
2 daysDay(s) Performed
Monday through Friday
Clinical Reference
1. Vasoo S, Cunningham SA, Kohner P, et al: Comparison of a novel, rapid chromogenic biochemical assay, the Carba NP test, with the modified Hodge test for detection of carbapenemase-producing Gram-negative bacilli. J Clin Microbiol 2013;51(9):3097-3101
2. Nordmann P, Poirel L, Dortet L: Rapid detection of carbapenemase-producing Enterobacteriaceae. Emerg Infect Dis 2012;18:1503-1507
Method Name
Colorimetric Detection of Carbapenem Hydrolysis
Specimen Type
VariesShipping Instructions
1. See Infectious Specimen Shipping Guidelines in Special Instructions for shipping information.
2. Place specimen in a large infectious container (T146) and label as an etiologic agent/infectious substance.
Necessary Information
Specimen source and organism identification are required.
Specimen Required
Specimen Type: Organism
Supplies: Infectious Container, Large (T146)
Container/Tube: Slant
Specimen Volume: Isolate
Collection Instructions: Submit Enterobacteriaceae or Pseudomonas aeruginosa isolate in pure culture (ie, not mixed with other organisms), actively growing.
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | ||
Refrigerated |
Reference Values
Negative
Test Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
CARNP | Carbapenemase-Carba NP Test | 74676-8 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
CARNP | Carbapenemase-Carba NP Test | 74676-8 |
Additional Tests
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
CARNB | Carbapenemase-Carba NP Test | No | Yes |
Special Instructions
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
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