Yale New Haven Hospital

Department of Laboratory Medicine
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C. difficile assay

Lab Section: 



Lab Location: 

Main Lab

Test ID: 




Clostridium difficile Assay


Alere C diff Quik Chek Complete




Test performed 4 times daily Mon-Fri and 2-3 times daily on weekends.

Specimen Requirements: 

Collect 2.0 mL Semi-solid or liquid stool in a sterile container.
Pediatric volume: 0.5 mL
Unacceptable conditions: Solid stools, samples submitted on patients less than 1 year of age, and samples submitted less than 3 days apart, unless the clinical condition has changed.



Initial rapid screen detects C. difficile GDH antigen and Toxins A and B.  If positive for both or negative for both GDH and toxin, final report issued.

If positive for GDH bacterial antigen only, sample is reflexed to cytotoxin neutralization test. Cytotoxin neutralization is more sensitive than the rapid toxin test and is read at 4, 24 and 48 hours after cell culture inoculation. Toxin positivity correlates with disease.

PCR is available on request by GI, ID, or Infection Control specialists for toxin negative samples if suspicion is high.  PCR can remain positive after therapy and detects carriers as well as disease.

Reference Interval: 


Last Changed: 

8/25/2017 9:35:32 AM

Last Reviewed: 

8/25/2017 9:35:32 AM