Test Catalog

Test Id : CDIF

Clostridioides difficile Culture, Varies

Useful For
Suggests clinical disorders or settings where the test may be helpful

Providing an isolate suitable for antimicrobial susceptibility testing.


Culture provides definitive evidence of the presence of the bacterium, Clostridioides difficile in feces, providing an isolate for antimicrobial susceptibility testing.

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test Id Reporting Name Available Separately Always Performed
ANAID Anaerobe Ident No, (Bill Only) No
RMALA Id MALDI-TOF Mass Spec Anaerobe No, (Bill Only) No
ISAN Anaerobe Ident by Sequencing No, (Bill Only) No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Method Name
A short description of the method used to perform the test

Conventional Culture Technique

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

C. difficile Culture

Lists additional common names for a test, as an aid in searching

Antibiotic-associated diarrhea

C. difficile, Stool

C. difficile, Feces

Antibiotic-associated pseudomembranous colitis

C difficile

Clostridium difficile



C. difficile

C difficile, Feces

C difficile, Stool

Clostridioides difficile

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Specimen Type
Describes the specimen type validated for testing


Ordering Guidance

Culture is not the preferred diagnostic test for Clostridioides difficile. Order CDFRP / Clostridioides (Clostridium) difficile Toxin, Molecular Detection, PCR, Feces for routine diagnostic testing.

Additional Testing Requirements

If susceptibility testing is needed; also order MMLSA / Antimicrobial Susceptibility, Anaerobic Bacteria, MIC, Varies. Susceptibility testing, when ordered, would routinely include metronidazole and vancomycin. If susceptibilities are not appropriate and will not be performed, MMLSA will be canceled.

Shipping Instructions

See Infectious Specimen Shipping Guidelines in Special Instructions for shipping information.

Necessary Information

Specimen source is required.


Question ID Description Answers
Q00M0077 Specimen Source

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Submit only 1 of the following specimens:



Specimen Type: Preserved feces

Supplies: Culture and Sensitivity Stool Transport Vial (T058)

Container/Tube: Commercially available transport system specific for recovery of enteric pathogens from fecal specimens (15 mL of non-nutritive transport medium containing phenol red as a pH indicator, either Cary-Blair or Para-Pak C and S)

Specimen Volume: Representative portion of feces; 5 mL

Collection Instructions:

1. Collect fresh fecal specimen and submit in container with transport medium.

2. Place feces in preservative within 2 hours of collection.

Additional Information: Only diarrheal (ie, unformed) feces should be tested. Testing formed feces for Clostridioides difficile is generally not clinically indicated.

Specimen Stability Information: Ambient (preferred) 96 hours/Refrigerated 96 hours/Frozen 7 days



Specimen Type: Unpreserved feces


Stool container, Small (Random), 4 oz (T288)

Stool Collection Kit, Random (T635)

Container/Tube: Stool container

Specimen Volume: Representative portion of feces

Collection Instructions: Collect fresh feces and submit representative sample in stool container.

Additional Information: Only diarrheal (ie, unformed) feces should be tested. Testing formed feces for C difficile is generally not clinically indicated.

Specimen Stability Information: Ambient (preferred) 72 hours/Frozen 7 days


Specimen Type: Fresh tissue or biopsy

Sources: Colon

Supplies: Anaerobe Transport Tube (T588)

Specimen Volume: Entire collection, 1-2 cm(3)

Collection Instructions: Aseptically collect a 1 to 2 cm(3) piece of tissue whenever possible. In general, a larger piece of tissue is preferred. Submit in an anaerobic transport tube.

Specimen Stability Information: Ambient 72 hours


If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Client Test Request (T728) with the specimen. 

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

Stool: 1 g or 5 mL

Tissue: 5 mm(3)

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Varies Varies

Useful For
Suggests clinical disorders or settings where the test may be helpful

Providing an isolate suitable for antimicrobial susceptibility testing.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Clostridioides difficile (formerly Clostridium difficile) can cause diarrhea and may cause pseudomembranous colitis. Overgrowth of toxin-producing C difficile in the colon leads to the production of toxins A and/or B by the organism and consequent diarrhea. C difficile infection should be suspected in patients with symptoms of diarrhea with risk factors such as current or recent use of antibiotics, a history of C difficile infection, current or recent hospitalization or placement in a nursing home or long-term care facility, age older than 65 years, gastric acid suppression, etc. C difficile infection is the most common cause of diarrhea in hospitalized patients and may lead to serious complications, including sepsis, bowel perforation, and increased overall mortality (especially in older patients). The incidence of C difficile infection has risen in the community and in healthcare settings. While culture is not the preferred means to diagnose C difficile-associated diarrhea, culture for C difficile provides an isolate suitable for antimicrobial susceptibility testing. Note that this test does not differentiate between toxin-producing and nontoxigenic strains of C difficile.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

No growth after 1 day of incubation.

Provides information to assist in interpretation of the test results

A positive result indicates the presence of viable Clostridioides difficile in feces.


A positive culture may be found with asymptomatic C difficile colonization with a toxin-producing or non-toxin-producing strain, or with C difficile-associated diarrhea.


A negative result indicates the absence of C difficile growth in culture.


Isolation of C difficile does not differentiate between toxin-producing and non-toxin-producing strains.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The assay must be performed on fresh feces, fresh-frozen feces, or feces in transport medium. Only diarrheal (ie, unformed) feces should be tested.


Submission of more than 1 specimen for testing is not recommended.


Repeated testing during a single episode of diarrhea is not recommended.


Testing of asymptomatic patients (ie, without diarrhea) or for test of cure is not recommended.


Patients may asymptomatically carry Clostridioides difficile.


Testing of colostomy, ileostomy, or colonoscopically collected specimens has not been validated.

Supportive Data

Fifty fecal specimens in Cary Blair transport media that were previously determined as positive for Clostridioides difficile by toxin polymerase chain reaction were subcultured directly onto CHROMagar C difficile plates. Plates were incubated under anaerobic conditions at 37 degrees C for 24 hours in accordance with the manufacturer's recommendation. C difficile identification was performed by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) directly from bacterial colony growth on CHROMagar plates. Using this method, C difficile was identified from 47 of 50 fecal specimens, corresponding with a 94% recovery rate. Two specimens that did not yield C difficile on CHROMagar media also failed to produce growth on conventional C difficile selective media (taurochocolate, cycloserine, cefoxitin, fructose agar; TCCFA). One specimen was recovered by the TCCFA media, but not by the CHROMagar C difficile media. Organisms other than C difficile were not recovered on CHROMagar, corresponding to 100% analytical specificity.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Cohen SH, Gerding DN, Johnson S, et al: Clinical practice guidelines for Clostridium difficile infection in adults: 2010 update by the society for healthcare epidemiology of America (SHEA) and the infectious diseases society of America (IDSA). Infect Control Hosp Epidemiol. 2010 May;31(5):431-455

2. Lawson PA, Citron DM, Tyrrell KL, Finegold SM: Reclassification of Clostridium difficile as Clostridioides difficile (Hall and O'Toole 1935) Prevot 1938. Anaerobe. 2016 Aug;40:95-99. doi. 10.1016/j.anaerobe.2016.06.008

3. Oren A, Garrity GM: List of new names and new combinations previously effectively, but not validly, published. Int J Syst Evol Microbiol. 2016 Nov;66(11):4299-4305. doi 10.1099/ijsem.0.001585

Method Description
Describes how the test is performed and provides a method-specific reference

Specimens are directly inoculated onto a CHROMagar Clostridioides difficile plate which is incubated anaerobically at 35 to 37 degrees C for 24 hours. Plates are observed for characteristic fluorescence using ultra violet light at 365 nm. Fluorescent colonies are identified by MALDI-TOF MS or 16S ribosomal RNA gene sequencing.(Instruction manual: CHROMagar C. difficile, NT-EXT-078 V4.0 / 10-Sept-2015, Available at: www.CHROMagar.com)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

2 to 6 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


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  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

87081-C. difficile Culture

87076-Anaerobe Ident (if appropriate)

87076-Id MALDI-TOF Mass Spec Anaerobe (if appropriate)

87153-Anaerobe Ident by Sequencing (if appropriate)

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
CDIF C. difficile Culture 562-9
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
CDIF C. difficile Culture 562-9

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports