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Test Code LAB4886 Clostridioides (Clostridium) difficile Testing, Stool

Methodology

Enzyme Immunoassay (EIA):

This assay detects C. difficile antigen, glutamate dehydrogenase (GDH), as a screen for the presence of C. difficile and confirms the presence of toxigenic C. difficile by detecting toxins A/B in unformed fecal specimens from persons suspected of having C. difficile disease.

 

Real-time polymerase chain reaction (RT-PCR) – (available as add on only):

This assay is a real-time polymerase chain reaction (RT-PCR) using the GeneXpert Dx System for the detection of C. difficile Toxin B in unformed (liquid or soft) stool specimens from individuals with high suspicion of having C. difficile infection. 

Note: PCR is performed by request only in situations of positive GDH and negative free toxin, OR will automatically reflex in situations of invalid antigen EIA results. Testing must be added on within 96 hours of specimen collection. Call Laboratory Customer Service at 314-362-1470 to request add-on.

 

Literature References: 

 

TECHLAB® C. DIFF QUIK CHEK COMPLETE® Package Insert.  TechLab®, Blacksburg, VA.  Revised 06/2021

 

Xpert® C. difficile Assay – GeneXpert Package Insert. Cepheid, Sunnyvale, CA. 300-8023, Rev. G. October 2019

 

Clinical Practice Guidelines for Clostridium difficile Infection in Adults and Children: 2017 Update by the  Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA). McDonald LC, Gerding DN, Johnson S, Bakken JS, Carroll KC, Coffin SE, Dubberke ER, Garey KW, Gould CV, Kelly C, Loo V, Shaklee Sammons J, Sandora TJ, Wilcox MH. Clin Infect Dis. 2018 Mar 19;66(7):987-994. doi: 10.1093/cid/ciy149. PMID: 29562266

Performing Laboratory

Barnes-Jewish Hospital Laboratory

Specimen Requirements

Specimen Type: Stool, fresh liquid or soft - Formed stool is not acceptable.

Container/Tube: Leakproof screw-capped, sterile container 

Specimen Volume: ≥1 mL

Specimen Minimum Volume: 0.5 mL

 

Additional Information:

  1. Specimen source is required.
  2. If transport is delayed, refrigerate specimen at 2-8˚C.
  3. Send only 1 specimen per calendar day.
  4. Repeat testing is not recommended and should not be routinely preformed.  If repeat testing is clinically indicated for a patient that has had a negative test, wait 96 hours before sending another specimen.
  5. If patient has a positive test, test of cure is not recommended and should not be performed.  As the minimum recommended duration of therapy is 10 days, if repeat testing is needed on a previously positive patient wait at least 10 days before sending another specimen.

Specimen Transport Temperature

Ambient/Refrigerate OK

Reference Values

Negative, free toxin

Day(s) Test Set Up

Monday through Sunday

 

Turnaround Time:
STAT: not available
Routine: results within 8 hours from receipt in laboratory

Test Classification and CPT Coding

87449

87324

87493 (if PCR performed)

 

Additional Information

For BJH Laboratory Use Only


Minimum Volume: 0.5 mL of liquid stool or 0.5 g of soft stool in a leakproof screw-capped, sterile container


Laboratory Processing Instructions:
Antigen test performed in BJH Microbiology

PCR test performed in BJH Molecular Infectious Disease