Clostridium Difficile by PCR (CDIPC) Outpatients


Test code:





Clostridium, Clostridium Difficile, Difficile Toxin, C Diff, CDIFF


Performing Lab:

Park Nicollet Flow Cytometry/Molecular



Specimen Requirements:



Fresh, liquid, or soft stool specimen (2 cc minimum), uncontaminated by urine, is collected in a clean container.  Only one specimen per 7 days is accepted. 

  • Transfer liquid stool or soft stool into a clean container.  Avoid mixing with toilet paper, water, urine, or soap.
  • Label the container with patient information.  Use appropriate label.  Send any additional labels with the specimen.





Transport Temperature:

Refrigerate (2 to 8 degrees C).  Transport to lab ASAP





Lab processing instructions:





Pathway:  Transport to laboratory specimen processing area.  Specimen processing area will deliver to Methodist Microbiology set up bench.

Clinics:  Dip swabs in stool and send labeled swabs to MH lab.


Same as above






5 days refrigerated






Unlabeled specimen; formed stool; swabs; stool in any kind of preservative.





Qualitative detection of C. difficile Toxin B gene (tcdB); PCR (Polymerase chain reaction)



Days Performed:

Monday - Friday




1-3 days



CPT Code:




Reference Ranges:



Additional Information:   

Do not test patient without signs or symptoms of CDI for C. difficile

  • The standard for suspicion of C.difficile infection is clinically significant diarrhea defined as 4 or more loose stools in a 24 hour period
  • C. difficile testing will be limited to one specimen every 7 days.  Repeat samples received within 7 days will be cancelled.  The most recent literature does not support frequent repeat real time PCR testing as the sensitivity and specificity of this test is 94-100%.
  • In the case of equivocal results, a new sample should be collected and tested within 2 weeks of first testing.  If the result is still equivocal, the sample should sent for Clostridium difficile cytotoxin cell assay, Test Code: 60851 to ARUP.
  • A negative result alone may not rule out the possibility of C.difficile associated colitis or diarrhea. 
  • A positive result alone should not be used to diagnose C.difficile associated colitis or diarrhea.  C. difficile should always be evaluated along with clinical signs and patient history.
  • Children under 2 years of age, interpret in clinical context.
  • Resources:

o   “Diagnosing CDI”  Managing Infection Control, August 2009


Last updated 12/03/2013, bertspa