Test Catalog

Test Id : CRPCR

Carbapenem Resistance Genes, Molecular Detection, PCR, Rectal Swab

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detecting and differentiating the blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP gene sequences associated with carbapenem intermediate or resistant results


Aiding in infection control in the detection of gastrointestinal colonization of patients in healthcare settings with bacteria not susceptible to carbapenems using rectal or perirectal swabs

Method Name
A short description of the method used to perform the test

Real-Time Polymerase Chain Reaction (RT-PCR)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Carbapenem Resistance Genes, PCR

Lists additional common names for a test, as an aid in searching

Carbapenem resistant CRE

Carbapenem resistant Enterobacteriaceae

Carbapenem resistant Enterobacterales

Carbapenem resistant Pseudomonas aeruginosa

Carbapenem resistant Acinetobacter species

Carbapenem resistant gram-negative bacilli

Carbapenem non-susceptible











Specimen Type
Describes the specimen type validated for testing


Ordering Guidance

This test is performed on rectal and perirectal swab specimens from patients at risk for intestinal colonization with bacteria not susceptible to carbapenem antimicrobials.


Other mechanisms of carbapenem resistance, including carbapenemases not targeted by this assay, porin mutations, and hyperexpression of drug efflux pumps, may result in carbapenem resistance. These mechanisms are not detected by this assay.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Specimen Type: Rectal/perirectal swab

Supplies: Culturette (BBL Culture Swab) (T092)

Container/Tube: Culture transport swab

Specimen Volume: Entire collection


If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

See Specimen Required

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross lipemia Reject
Incorrect swab used Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Swab Ambient 5 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detecting and differentiating the blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP gene sequences associated with carbapenem intermediate or resistant results


Aiding in infection control in the detection of gastrointestinal colonization of patients in healthcare settings with bacteria not susceptible to carbapenems using rectal or perirectal swabs

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

The global spread of carbapenemase-producing Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter species (organisms not susceptible to carbapenem antimicrobials) is a critical public health issue. These bacteria are often resistant to all beta-lactam agents and, frequently, are also resistant to multiple classes of other antimicrobial agents, leaving very few treatment options. Tracing the spread of organisms not susceptible to carbapenems is complicated by the diversity of carbapenem-hydrolyzing enzymes that have emerged and the ability of the genes to spread among multiple bacterial species.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Not detected

Provides information to assist in interpretation of the test results

A detected result is when blaKPC, blaNDM, blaVIM, blaOXA-48, or blaIMP target DNA is detected. This indicates the presence of gene sequences associated with carbapenem intermediate or resistant results.


A not detected result is when blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP target DNA is not detected.


A not detected Xpert Carba-R Assay result does not preclude the presence of other carbapenem resistance mechanisms.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The Xpert Carba-R Assay detects blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP from rectal and perirectal specimens and is not for bacterial identification. Detection of these gene sequences does not indicate the presence of viable organisms.


The Xpert Carba-R Assay is not a genetic-relatedness subtyping tool and does not report variants of the blaKPC, blaNDM, blaVIM, blaOXA-48, or blaIMP genes.


Imipenemase-type metallo-beta-lactamase (IMP) types detected by this assay include only IMP-1, 2, 4, 6, 10, and 11.


Rectal and perirectal specimens from pediatric patients have not been evaluated.


Certain bacterial species, such as Pseudomonas aeruginosa and Acinetobacter baumannii, have been shown to exhibit resistance to the carbapenem antimicrobial ertapenem due to intrinsic resistance mechanisms.


The detection of OXA-carbapenemase genes, besides blaOXA-48 and blaOXA-181, has not been evaluated with this assay.


Variants or alterations in primer or probe binding regions may affect detection of current, new, or unknown blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP variants, resulting in a false-negative result.


Testing with the Xpert Carba-R assay should be used as an adjunct to other available methods.


Cocolonization with 2 or more carbapenemase-producing organisms has been reported with the Xpert Carba-R Assay, but it is rare.


Carbapenem-resistant anaerobes potentially present in fecal specimens have not been evaluated by the Xpert Carba-R assay.

Supportive Data

The Xpert Carba-R Assay is a US Food and Drug Administration-cleared test. The Xpert Carba-R was further verified for use with a Zeptometrix verification panel and organisms (Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter bacteria) with known carbapenem antimicrobial susceptibility test results. The verification passed, and this test is acceptable for patient testing.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. McConville TH, Sullivan SB, Gomez-Simmonds A, Whittier S, Uhlemann AC. Carbapenem-resistant Enterobacteriaceae colonization (CRE) and subsequent risk of infection and 90-day mortality in critically ill patients, an observational study. PLoS One. 2017;12(10):e0186195

2. Tenover FC, Nicolau DP, Gill CM. Carbapenemase-producing Pseudomonas aeruginosa an emerging challenge. Emerg Microbes Infect. 2022;11(1):811-814

3. Clinical and Laboratory Standards Institute (CLSI). Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically. 11th ed. CLSI standard M07. CLSI; 2018

Method Description
Describes how the test is performed and provides a method-specific reference

The GeneXpert Dx System automates and integrates sample purification, nucleic acid amplification, and detection of the target sequence in simple or complex specimens using a real-time PCR assay. The system requires the use of single-use disposable cartridges that hold the PCR reagents and host the PCR process. Because the cartridges are self-contained, cross-contamination between samples is eliminated. The primers and probes in the Xpert Carba-R Assay detect proprietary sequences for the blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP gene sequences associated with carbapenem intermediate or resistant results in gram-negative bacteria.(Package insert: Xpert Carba-R. Cepheid; 01/2018)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 day

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

5 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
CRPCR Carbapenem Resistance Genes, PCR 85502-3
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
IMPCR IMP Resistance Gene 85498-4
VIMCR VIM Resistance Gene 85501-5
NDMCR NDM Resistance Gene 73982-1
KPPCR KPC Resistance Gene 49617-4
OXACR OXA-48-like Resistance Gene 85503-1

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | PHP Pdf | CMS Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports