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24856 C difficile Toxin,Nucleic Acid

C difficile Toxin,Nucleic Acid
Test Code: CDNAT
Synonyms/Keywords
​C. difficile Toxin PCR, Clostridium difficile Toxins A and B, CTOX, C diff, CDNAT
Useful For

Clostridium difficile is the primary infectious cause of nosocomial acute diarrhea, and a major cause of nosocomial diarrhea overall. Consider C. difficile nucleic acid testing in all hospitalized patients over twelve months of age with acute diarrhea, especially those with a recent history of antibiotic exposure. See Adult Inpatient Testing Algorithm. C. difficile can also be a cause of community-associated diarrhea in the outpatient. In such cases fecal bacterial culture should also be ordered to rule out bacterial enteropathogens (see Culture, Feces).

This assay should not be used for screening asymptomatic individuals, and should only be used to test patients with signs and symptoms of toxigenic C. difficile infection. In accordance with the 2017 IDSA and SHEA guidelines, no more than 1 specimen should be submitted within 7 days during the same episode of diarrhea.

Testing of stools from infants less than 1 year of age for C. difficile is discouraged due to the high rate of asymptomatic carriage of toxigenic C. difficile in this population. A positive C. difficile toxin gene test in infants is not conclusive evidence of C. difficile disease, other causes of diarrhea should be investigated. (Pediatr Infect Dis J 2009;28: 145-146).

The Clostridium difficile Nucleic Acid Test is a Real Time PCR in vitro diagnostic test for the qualitative detection of toxigenic Clostridium nucleic acids isolated and purified from liquid or unformed stool specimens obtained from symptomatic patients.

Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​ Feces​ Leak-proof container​ 2.0 mL​ 1.0 mL​ 100 uL
Collection Processing Instructions

Fresh, unpreserved, unformed (i.e. takes the shape of the container at room temperature) feces in leak-proof container.

For more information on Specimen Collection Media/Swab, see Specimen Transport Pictorial.

Specimen Stability Information
Specimen Type Temperature Time
Feces​​ Refrigerate​ 7 days​
Frozen​ 7 days
Rejection Criteria
Formed fecal specimens
More than one specimen within 7 days
Specimens transported in Cary-Blair or C & S transport medium
​Stool collected on wooden tongue depressor
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
DTC​ Monday through Sunday ​3 hours ​Nucleic acid test (PCR based) 
​Eau Claire Monday through Sunday ​6 hours Nucleic acid test (PCR based) ​
​Flambeau Hospital Monday through Sunday ​6 hours ​Nucleic acid test (PCR based) 
​Ladysmith Medical Center ​Monday through Sunday ​6 hours Nucleic acid test (PCR based) ​
Lakeview Medical Center​ ​Monday through Sunday ​6 hours ​Nucleic acid test (PCR based)
​​Marshfield ​Monday through Sunday
6-8 hours*
​Nucleic acid test (PCR based) ​
*Testing performed once/day.
​For Marshfield, sample must be received in the lab by 0400 to be tested same day​. ​ ​ ​
Test Information
Clostridium difficile infection is a toxin-mediated disease and the majority of C. diff strains produce two toxins including Toxin A, an enterotoxin, and Toxin B, a cytotoxin; however, strains have been isolated that are Toxin A-/B+. Toxin A+/B- strains have been reported but the incidence of these variants appears to be extremely rare. Although both Toxin A+/B+ and Toxin A-/B+ strains circulate in the population, strains that are Toxin A+/B+ are currently dominant.​
Reference Range Information
All Performing Sites:   Negative
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​87493
Synonyms/Keywords
​C. difficile Toxin PCR, Clostridium difficile Toxins A and B, CTOX, C diff, CDNAT
Ordering Applications
Ordering Application Description
​Centricity ​C difficile Toxin, Nucleic Acid
​Cerner ​Clostridium difficle Toxin, NAT (CDNAT)
​Clinical Order Manager ​Clostridium diff. Toxin NAT
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​ Feces​ Leak-proof container​ 2.0 mL​ 1.0 mL​ 100 uL
Collection Processing

Fresh, unpreserved, unformed (i.e. takes the shape of the container at room temperature) feces in leak-proof container.

For more information on Specimen Collection Media/Swab, see Specimen Transport Pictorial.

Specimen Stability Information
Specimen Type Temperature Time
Feces​​ Refrigerate​ 7 days​
Frozen​ 7 days
Rejection Criteria
Formed fecal specimens
More than one specimen within 7 days
Specimens transported in Cary-Blair or C & S transport medium
​Stool collected on wooden tongue depressor
Useful For

Clostridium difficile is the primary infectious cause of nosocomial acute diarrhea, and a major cause of nosocomial diarrhea overall. Consider C. difficile nucleic acid testing in all hospitalized patients over twelve months of age with acute diarrhea, especially those with a recent history of antibiotic exposure. See Adult Inpatient Testing Algorithm. C. difficile can also be a cause of community-associated diarrhea in the outpatient. In such cases fecal bacterial culture should also be ordered to rule out bacterial enteropathogens (see Culture, Feces).

This assay should not be used for screening asymptomatic individuals, and should only be used to test patients with signs and symptoms of toxigenic C. difficile infection. In accordance with the 2017 IDSA and SHEA guidelines, no more than 1 specimen should be submitted within 7 days during the same episode of diarrhea.

Testing of stools from infants less than 1 year of age for C. difficile is discouraged due to the high rate of asymptomatic carriage of toxigenic C. difficile in this population. A positive C. difficile toxin gene test in infants is not conclusive evidence of C. difficile disease, other causes of diarrhea should be investigated. (Pediatr Infect Dis J 2009;28: 145-146).

The Clostridium difficile Nucleic Acid Test is a Real Time PCR in vitro diagnostic test for the qualitative detection of toxigenic Clostridium nucleic acids isolated and purified from liquid or unformed stool specimens obtained from symptomatic patients.

Reference Range Information
All Performing Sites:   Negative
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
DTC​ Monday through Sunday ​3 hours ​Nucleic acid test (PCR based) 
​Eau Claire Monday through Sunday ​6 hours Nucleic acid test (PCR based) ​
​Flambeau Hospital Monday through Sunday ​6 hours ​Nucleic acid test (PCR based) 
​Ladysmith Medical Center ​Monday through Sunday ​6 hours Nucleic acid test (PCR based) ​
Lakeview Medical Center​ ​Monday through Sunday ​6 hours ​Nucleic acid test (PCR based)
​​Marshfield ​Monday through Sunday
6-8 hours*
​Nucleic acid test (PCR based) ​
*Testing performed once/day.
​For Marshfield, sample must be received in the lab by 0400 to be tested same day​. ​ ​ ​
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​87493
For most current information refer to the Marshfield Laboratory online reference manual.