Test Overview
Test Methodology

PCR/EIA

Test Usage

Patients with new-onset diarrhea without an alternative explanation should be considered for CDI testing. Diarrhea is defined as ≥3 unformed stools in 24 hours.

Reference Range *

Not detected

Test Limitations

Per Michigan Medicine C. difficile Infection Guidelines, testing is rarely indicated or recommended for infants less than 12 months and will be rejected. Approval from Pediatric Infectious Disease is required to perform testing on patients less than 12 months of age.
There is no role for performing both GIPAN and PCRCD simultaneously or performing a PCRCD after a GIPAN as the tests results for C. difficile are essentially the same.
PCRCD may remain positive for up to 30 days after successful treatment; tests of cure should not be performed.

Test Details
Update Type: Replacement Test
Test Updated: 06/23/2021
Days Set Up
Daily at least 3x per day
Analytic Time

Results within 2-6 hours of receipt in lab

Soft Order Code
PCRCD
MiChart Code
C. difficile PCR/toxin algorithm
Synonyms
  • Antibiotic Associated Colitis (AAC)
  • Colitis, Clostridium difficile
  • Pseudomembranous Colitis Toxin Assay
  • PCRCD
  • CLOST. DIFFICILE TOXIN B, PCR
  • CDIFF
  • Clostridium difficile Antigen
  • Clostridium difficile Toxin
  • CDTOX
  • CLOSTRIDIUM DIFFICILE TOXIN
  • CLOSTRIDIUM DIFFICILE
  • GDH Screen
  • GDH Antigen
Laboratory
Microbiology
Section
Microbiology
Specimen Requirements
Collection

Collect at least 5 mL of fresh stool and place in a sterile screw-capped container with no preservative. Formed stools are not acceptable. Refrigerate and send specimen immediately after collection. Specimen must be received within 24 hours of collection. Collect no more than one specimen in a 7-day period. See MLabs Stool Specimen Collection Instructions available online at https://mlabs.umich.edu/media/175 for patient instructions.

Rejection Criteria
Specimens retrieved from a diaper or contaminated with urine are not acceptable.
Formed stools are not acceptable. (Exceptions made for BMT patients where indicated)
Specimen received >24 hours following collection.
Repeat C difficile testing within 7 days of a negative C. difficile test or within 14 days of a positive C. difficile test is not acceptable.
Stool in preservative, such as Cary Blair (Stool C&S transport), is not acceptable.
Testing ordered on patients ≤1 year old is not acceptable.

If a CDIFF test must be cancelled after being received by the laboratory, laboratory staff will contact the care team via alpha page to notify them that the test will be cancelled.
Contraindications
A large percentage of hospitalized patients have other reasons for diarrhea, such as laxatives, chemotherapy, and enteral tube feeds. When possible, one should consider first stopping therapies to which diarrhea may otherwise be attributed (e.g., laxatives), and then reassess prior to testing for CDI.
Normal Volume
5 mL liquid stool
Minimum Volume
5 mL liquid stool
Additional Information

If PCR for toxigenic C. difficile is positive, confirmation testing for C. difficile Toxin A/B by EIA will be performed at an additional charge. By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated.

Billing
CPT Code
87798
Fee Code
32277
Reflex CPT
87449
Reflex Fee Code
32397
NY State Approved
No