Please note that the website is being retired as of May 31, 2019. Please revise your bookmarks to use the Quest Test Directory for your inquiries:

Welcome to the new Quest Diagnostics Test Directory

Search with confidence for the right test! Use our helpful education resources, and tools to narrow your search by specialty and test category, and compare tests side-by-side.
Test Menu
Test Change Details
Allergy & Immunology
Cardiology & Coagulation
Infectious Disease
Women's Health
91664: Clostridium Difficile Toxin/gdh With Reflex To Pcr Print View
GDH Antigen IA  Not detected   
Toxin A and B IA  Not detected   

1 Stool 5 (1) g   Refrigerated - 72 Hour(s)/Frozen - 30 Day(s)  

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 recommended 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, confimation by NAAT is also recommended.

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 sterile container. Do not submit the diaper itself. Cap
securely. Do not use any preservative, media or additive.
Setup Schedule

Reported (Analytical Time)
Same day

CPT Codes

The CPT codes provided are based on AMA guidelines 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.

Reject Criteria: Formed stool; stool submitted in transport media or swab; rectal swab; unfrozen stoll >72 hours old.
Transport Temperature: Frozen If the GDH Antigen is detected and the Toxin A and B are not detected or the GDH Antigen is not detected and the Toxin A and B are detected, 16377-Clostridium difficile Toxin B, Qualitative Real Time PCR will be performed at an additional charge. (CPT code(s): 87493) New recommendations per the American Society for Microbiology recommend that screening assays for C. difficile toxin be combined with GDH antigen, with discordant results being confirmed by Nucleic Acid Amplification testing.

1996 - 2019 Quest Diagnostics Nichols Institute of Valencia
For test information, please call Client Services at 800-421-4449.

San Francisco Web Design & Database