C. difficile DNA PCR w/RFX Toxin (CDD)
Department: Microbiology
Test Synonym(s): LAB5888, CDD, Clostridium difficile, C. difficile DNA PCR with reflex to free toxin
Test Components: C. diff DNA PCR, C. Diff PCR Interp, C. diff EIA Toxin
CPT Codes: PCR: 87493; EIA: 87449
Methodology: DNA Amplification Assay, PCR positive will reflex to C. diff EIA toxin
Reference Range: Not detected
Tube Type: Sterile container (scew top tightly sealed)
Specimen: Stool, Non-formed
Alternate Specimen: Stool, Non-formed in Cary Blair Transport Media
Volume: 1 mL
Minimum Volume: 1 mL
Temperature: Refrigerated (2-8C)
Stability: Refrigerated (2-8C): stored and transported
Reasons for Rejection: Formed stool, leaking container, more than two negative samples in a 7 day period or 1 positive sample in a 7 day period
Days Performed: Daily
Times Performed: 1-2 times per day
TAT: 24 hours
Significance: Current guidelines recommend a multiple analyte algorithm for C. difficile testing which includes a nucleic acid amplification test performed with free toxin antigen detection. Please see below for interpretative data/clinical significance: 1. C. difficile PCR – Not Detected: No toxigenic C. difficile detected. 2. C. difficile PCR – Detected, C. difficile toxin antigen – Detected: These results are consistent with C. difficile infection in the context of the patient’s clinical scenario. 3. C. difficile PCR – Detected, C. difficile toxin antigen – Not Detected: These results are suggestive of C. difficile colonization and may not reflect C. difficile infection requiring treatment. The significance of these results must be interpreted in the context of the patient’s clinical scenario.
Special Instructions: Testing for C.difficile should be performed on patients with clinically-significant diarrhea, defined as 3 or more loose stools per day for at least 1-2 days.Repeat stool testing for test of cure is NOT recommended. Providers should ensure that the patient has not been administered laxatives in the prior 24-48 hours as a possible explanation for the diarrheal symptoms.
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