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Test Code CDIFF C. difficile Toxin B PCR

Additional Codes

Epic: LAB253

Specimen Required

Sterile Container


Specimen Minimum Volume

3mL loose or liquid stool. Stool must take the shape of the container

Report Available

1-2 days

Clinical Significance

A positive result may indicate infection or colonization with Clostridium difficile harboring the Toxin B gene. The occurrence of Toxin gene A (+)/Toxin B (-) C. difficile is extremely rare and human disease has not been documented.
This assay should not be used as a test of cure and should not be run on formed/solid stool samples. Nucleic acid may persist after effective treatment and could be detected by this assay.


This assay detects the presence of a toxin gene. A positive does not indicate that toxin is being produced. This assay does not distinguish between viable and non-viable organisms. Test results are to be used in conjunction with information available from the patient clinical evaluation and other diagnostic procedures.
Colonization at rates up to 50% and higher have been reported in infants and rates up to 32% in cystic fibrosis patients.

Specimen Stability Information

Room temperature: 24 hours

Refrigerated: 5 days

Frozen: Unacceptable

Specimen Instructions

1) Submit stool in a dry, sterile, container (ensure that container is closed tightly to prevent leaks).
2) Apply patient identification label.

Note: Stool submitted in Cary Blair media is unacceptable for this assay. Stool that Is not loose enough to take the shape of the container is not acceptable for this assay.




Real-time polymerase chain reaction (PCR) for the amplification and detection of C. difficile toxin B gene DNA



Method Description

Real-time polymerase chain reaction for the amplification and detection of C. difficile toxin B gene DNA

Reject Due To


The following are situations in which rejection will occur:
Room temperature sample submitted >24 hours from collection time, Formed/Solid stool samples submitted (If in leus due to C. difficile is suspected and only formed stool can be collected, contact the laboratory to request sendout testing on rejected specimen), Repeat order within 7 days (without laboratory approval), Improperly labeled specimen, insufficient volume, specimen not submitted in appropriate transport container