Clostridium difficile Toxin/GDH with Reflex to PCR

Clostridium difficile Toxin/GDH with Reflex to PCR

Test Code

91664
87449, 87324
91664
87449, 87324
In-home collection is not available in your area through Quest Mobile.

Clinical Significance

Clostridium difficile Toxin/GDH with Reflex to PCR - After treatment with antibiotics, many patients develop gastrointestinal problems ranging from mild diarrhea to severe pseudomembranous colitis. This organism is an opportunistic anaerobic bacterium that grows in the intestine once the normal flora has been altered by the antibiotic. For diagnosis of toxigenic C. difficile, current practice guidelines from the CDC recommend confirmation by Nucleic Acid Amplification Testing (NAAT) if the glutamate dehydrogenase of C. difficile (GDH) Antigen is positive, and toxin is not detected by Enzyme immunoassay. Additionally, if toxin is detected without the presence of GDH antigen, confirmation by NAAT is also recommended.

Test Resources

Test FAQ

Clostridium (Clostridioides) difficile Diagnostic Testing

Algorithm

Differential Diagnosis of Inflammatory Bowel Disease

Clinical Focus

Inflammatory Bowel Disease: Laboratory Support for Diagnosis and Management

Test Summary

Clostridium difficile Toxin/GDH With Reflex to PCR

Test Details

Includes

  • If GDH Antigen is detected and Toxin A and B are not detected, then Clostridium difficile Toxin B, Qualitative, Real-Time PCR will be performed at an additional charge (CPT code(s): 87493).
    or
    If GDH Antigen is not detected and Toxin A and B are detected, then Clostridium difficile Toxin B, Qualitative, Real-Time PCR will be performed at an additional charge (CPT code(s): 87493).

Methodology

Immunoassay (IA)

Reference Range(s)

Not detected

LOINC® Codes, Performing Laboratory

Service Area must be determined
If GDH Antigen is detected and Toxin A and B are not detected, then Clostridium difficile Toxin B, Qualitative, Real-Time PCR will be performed at an additional charge (CPT code(s): 87493).
or
If GDH Antigen is not detected and Toxin A and B are detected, then Clostridium difficile Toxin B, Qualitative, Real-Time PCR will be performed at an additional charge (CPT code(s): 87493).

Methodology

Immunoassay (IA)

Reference Range(s)

Not detected
Service Area must be determined

Preferred Specimen(s)

5 grams or 5 mL unformed stool

Minimum Volume

1 gram or 1 mL

Collection Instructions

Collect fresh stool in sterile, leak-proof container without media, preservative, or metal ion. For patients requiring the use of diapers, first line the diaper with clean plastic to prevent absorption. Then transfer 5 grams or 5 mL of the stool specimen from the plastic lined diaper to the sterile container.
Do not submit the diaper itself. Cap securely. Do not use any preservative, media or additive.

Transport Container

Clean plastic screw-cap, leak-proof container

Transport Temperature

Frozen

Specimen Stability

  • Room temperature: Unacceptable
  • Refrigerated: 72 hours
  • Frozen: 30 days

Reject Criteria

Formed stool • Stool submitted in transport media or swab • Rectal swab • Unfrozen stool >72 hours old • Received room temperature

Setup Schedule

Service Area must be determined
5 grams or 5 mL unformed stool
1 gram or 1 mL
Collect fresh stool in sterile, leak-proof container without media, preservative, or metal ion. For patients requiring the use of diapers, first line the diaper with clean plastic to prevent absorption. Then transfer 5 grams or 5 mL of the stool specimen from the plastic lined diaper to the sterile container.
Do not submit the diaper itself. Cap securely. Do not use any preservative, media or additive.
Clean plastic screw-cap, leak-proof container
Frozen
Room temperature: Unacceptable
Refrigerated: 72 hours
Frozen: 30 days
Formed stool • Stool submitted in transport media or swab • Rectal swab • Unfrozen stool >72 hours old • Received room temperature
Service Area must be determined
In-home collection is not available in your area through Quest Mobile.
Test Details

Clinical Significance

Test Resources

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.

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