Eurofins Biomnis code

GDH

Synonyms

• toxin

Specialty

Infectious

Clinical significance

Clostridium difficile is an anaerobic bacteria present in the gastrointestinal tract. Its presence is generally symptom-free but may become pathogenic after an imbalance in the gastrointestinal flora (antibiotic therapy for example) when a toxin-secreting strain has emerged. Only these toxigenic strains are pathogenic and in a hospital setting require measures to isolate the patient. The spectrum of toxin-secreting C. difficile infections is broad: from simple diarrhoea to pseudomembranous colitis. Methods of biological diagnosis are based on 2 categories of tests: identifying the bacteria or the toxins. These tests have their own costs and performance. Algorithms for biological detection of C. difficile and its toxins therefore differ according to laboratories and hospital sites. GDH (glutamate dehydrogenase) is an enzyme present in C. difficile, and a positive result for GDH in stool marks the existence of C. difficile. Testing for C. difficile GDH has an excellent negative predictive value and is therefore an excellent first intention test. Current guidelines routinely recommend testing for toxins if C. difficile is present. We will therefore routinely test for toxins A and B using FIA (combining membrane immunochromatography and immunofluorescence) if GDH is positive for the same sample.

Preanalytics

• stool
•   Refrigerated

• A tube specifically for this analysis : No

Further information

.
If refrigerated, the sample must be processed at our laboratory within 72h from its collection. If sample older than 72h, please freeze.
This test is performed twice a week only (Mondays and Fridays). Please bear this in mind before you ship your request/sample.
Use purple bag (our ref. S14) for transport.
Please ensure that the sample's freezing and thawing dates and times are stated on the request form.
Failing to comply with any or all of the above may result in a non-conformity and our inability to perform the test.

Specific equipment available

• S14: Special mycobacteria transport bags are to be used

Methodology

Enzyme-immunoassay

Turnaround time

1 day