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Test Code LAB1235689 C. difficile GDH Antigen + Toxin A/B

Performing Laboratory

Rogue Regional Medical Center (RRMC)

 

Performing Department

Microbiology

Useful For

This test distinguishes the presence of toxigenic and/or non-toxigenic C. difficile.  The diagnosis of C. difficile associated diarrhea is made by combining a positive GDH test and toxin positivity, with clinical presentation. GDH (Glutamate Dehydrogenase) testing is a highly sensitive, rapid screening test for the presence of the bacteria, while toxin testing (toxin A and/or B) determines if the bacteria are producing toxins, which cause disease symptoms.

Special Instructions

Limit of one specimen every 7 days.

 

For inpatients, the patient must have at least 3 unformed stools within a 24 hour period, and must not have taken any laxatives.

Specimen Required

  • Specimen Type

Fresh, unformed, raw (unpreserved) stool. Cary Blair is also acceptable.

Place at least 1 to 2 tablespoons of unformed stool specimen in a sterile container (without additive).

  • Container type(s)

Sterile Cup

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Store specimen at 2-8ºC or sent on ice.

Specimen Retention Time:

Stable for up to 3 days when stored at 2-8ºC or > 3 days when stored frozen ≤ -10°C

Reject Due To

  • Lacking Two Patient Identifiers:
    • 1-Patient's First & Last name
    • 2-Patient's Date of Birth
  • Specimens received in Formalin
  • Specimens not maintained at ≤ 2-8ºC
  • All specimens that do not take the shape of the container will be rejected.

Day(s) Performed

  • Monday – Sunday (batch testing)
  • Turnaround – 24 hours

Method Name

LFA

Interpretation

GDH Positive, Toxin Negative* = Non-toxigenic C. difficile present

GDH Positive, Toxin Positive = Toxigenic C. difficile present

GDH Negative**, Toxin Negative = Negative for C. difficile

 

*A negative Toxin indicates C. difficile toxin is either absent in the specimen or is below the detection limit of the test

**A negative GDH result indicates C. difficile antigen is either absent in the specimen or is below the detection limit of the test.