Clostridium difficile Toxin by PCR




Test Mnemonic

CDPCR

Primary CPT Codes

  • 87493 - QTY (1), Amplification, Clostridium difficile

LOINC ®

54067-4

Aliases

  • Antibiotic Associated Diarrhea
  • Antibiotic Associated Pseudomembranous Colitis
  • C. difficile toxin
  • Clostridium difficile, Feces
  • Clostridium difficile, Stool

Performing Laboratory

Cleveland Clinic Laboratories


Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
5 mLStoolSterile container Refrigerated 

Minimum Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
1 mL     

Stability

Environmental Condition Description
Ambient24 hours
Refrigerated72 hours
FrozenFrozen stools have not been validated and will be rejected.

Days Performed

Sun - Sat

Turnaround Time

1 - 3 days

Methodology

Name Description
Polymerase Chain Reaction (PCR) 

Special Info

Due to the high sensitivity and negative predictive value of the PCR assay, only one sample per week is accepted for testing. Formed stools, samples from patients <2 yrs old, and specimen received in preservative, frozen, on swabs or wooden applicator sticks will be rejected.

Clinical Info

Unformed stools are tested for the presence of C. difficile toxin B gene by PCR. A positive PCR result for C. difficile may represent infection or colonization. The positive predictive value of the PCR assay for C. difficile infection (CDI) is highest for patients with significant diarrhea (3 or more unformed stools in 24 h) who do not have an alternative explanation (e.g., recent receipt of laxatives). Contact isolation is required for patients who are colonized or infected with C. difficile. Once a patient is diagnosed with CDI, therapeutic response should be based on clinical signs and symptoms; a “test of cure” should not be done since patients may remain colonized with toxin-producing strains following recovery.

Clinical Limitation

This test should not be ordered on potential fecal transplant donors. Submit specimen to SendOut Lab with an order for CDFRP. Potential Interfering substances include vagisil cream and zinc oxide paste.

Reflex Tests

The following additional test(s) may be ordered depending on results: