Test Catalog

Interpretive Handbook

Test 89676 :
Carbapenemase Detection, Modified Hodge Test

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

Resistance to antibiotic therapy via production of the enzyme carbapenemase by Klebsiella pneumoniae and other members of Enterobacteriaceae is becoming more common. This resistance is not always detected by conventional antimicrobial susceptibility testing, which may result in inappropriate antimicrobial therapy for the patient.


In Enterobacteriaceae, the gene blaKPC, which encodes KPC (Klebsiella pneumoniae carbapenemase) production, can be detected by real-time PCR. However, molecular methods have not been established for other carbapenemases.


The modified Hodge test, a phenotypic method, is recommended by the Clinical and Laboratory Standards Institute (CLSI) as the method to detect carbapenemases.

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

Determining carbapenem resistance

Interpretation Provides information to assist in interpretation of the test results

A positive result indicates the production of carbapenemase.


A negative result indicates the lack of production of carbapenemase.

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

This test is not routinely performed on Enterobacteriaceae determined to be fully resistant to carbapenems in the Mayo Microbiology Laboratory.

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.


Clinical References Provides recommendations for further in-depth reading of a clinical nature

The 2009 CLSI Standards for Antimicrobial Susceptibility Testing. CLSI Audioconference. Janet Hindler. Original air date: January 21, 2009