Confirmation of identification

Description of the test

The test consists of:

• demonstrating Clostridioides difficile in a sample or confirming it in a submitted isolate.
• testing for GDH (Glutamate dehydrogenase) in stool samples or on culture by enzyme immunoassay.

Purpose of the test

To confirm a diagnosis or discordant results.

Criteria for performing this test in the context of reference activities.

After contacting the laboratory.

Instructions for samples

The strain should be supplied as pure culture and freshly inoculated on a suitable medium. Suitable media are: deep gelose, platelet anaerobically packed type Anaerogen Compact (Oxoid), Anaerocult p (Merck) or other such methods, reduced media, thioglycolate or ‘ port a cul ’ type tubes. Although it is recommended to send cultures, the NRC also accepts stool samples.

Instructions for transport

• Transport is best done under anaerobic conditions. Transport at room temperature if the sample arrives at the lab within 6 hours of collection, or refrigerated within 72 hours (after that, stool samples can be frozen at -20°C). Make sure the tubes are tightly closed to prevent ‘leaking’; to this end, you can wrap the closed tube in parafilm.
• The sample is packed with absorbent material in a transport blister pack. This secondary packaging can also be a plastic zip-lock bag. It is then placed in an envelope or box.
• According to the applicable guidelines, the following symbol should be displayed on the outer packaging: UN3373 Biological substance category B.
• The NRC does not provide sample collection equipment.

Unacceptable requests

• Samples damaged or leaked in the packaging.
• Samples with missing information.

Turn around time (and frequency of analysis)

Maximum 10 working days. Analysis is carried out on request.

Reporting of test results

• By post.
• If specifically requested on the request form, by fax or e-mail.