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HelpTest Code CDIFS Clostridioides difficile Culture with Antimicrobial Susceptibilities, Varies
Ordering Guidance
Culture is not the preferred diagnostic test for Clostridioides difficile. For routine diagnostic testing, order CDPCR / Clostridioides difficile Toxin, PCR, Feces
Shipping Instructions
Necessary Information
Specimen source is required.
Specimen Required
Submit only 1 of the following specimens:
Patient Preparation: Patient should not use antacids, barium, bismuth, antidiarrheal medication, zinc oxide paste, Vagisil cream or oily laxatives prior to specimen collection.
Preferred:
Specimen Type: Preserved feces
Supplies: Culture and Sensitivity Stool Transport Vial (T058); Stool Collection Kit, Random (T635)
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 [T058])
Specimen Volume: Representative portion of feces; 5 mL
Collection Instructions:
1. Collect 1 gram or 5 mL 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 C difficile is not clinically indicated.
Specimen Stability Information: Ambient (preferred) 96 hours/Refrigerated 96 hours/Frozen 7 days
Acceptable:
Specimen Type: Unpreserved feces
Supplies: Stool container, Small (Random), 4 oz (T288); Stool Collection Kit, Random (T635)
Specimen Volume: Representative portion of stool
Collection Instructions: Collect fresh stool and submit representative sample in stool container.
Specimen Stability Information: Ambient (preferred) 72 hours/Frozen 7 days
Additional Information: Only diarrheal (i.e., unformed) stool should be tested. Testing formed stool for C difficile is 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 1-2 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
Useful For
Providing an isolate suitable for antimicrobial susceptibility testing to direct antimicrobial therapy of extraluminal infections and in cases of treatment failure
Reflex 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 |
| SANA | Anaerobe Suscep per agent | No, (Bill Only) | No |
| BATTA | Anaerobe Suscep Battery | No, (Bill Only) | No |
Testing Algorithm
When this test is ordered, the reflex tests may be performed and charged separately. Isolates of Clostridioides (Clostridium) difficile (1,2) will automatically have susceptibility testing performed and billed as appropriate. Antimicrobial agents appropriate to the organism and specimen source will be tested according to Mayo’s practice and the laboratory’s standard operating procedures.
See Anaerobic Bacteria Antimicrobials in Special Instructions to review the table which provides a listing of the antimicrobials routinely tested in our laboratory as well as antimicrobials that may be tested upon request. If the antimicrobial of interest is not listed in this table, contact Mayo Clinic Laboratories at 800-533-1710 and ask to speak to the Bacteriology Anaerobe Laboratory.
Anaerobe susceptibilities battery will routinely be performed at an additional charge. If fewer than 3 antibiotics will be reported, then anaerobe susceptibilities battery will be canceled and anaerobe susceptibilities per agent will be charged per antibiotic tested. Based on susceptibility criteria, anaerobe susceptibilities per agent may be performed at an additional charge.
Special Instructions
Reporting Name
C. difficile Culture + SuscSpecimen Type
VariesSpecimen Minimum Volume
Stool: 1 gram or 5 mL
Tissue: 5 mm(3)
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Reject Due To
| Fecal swab Specimen in Ecofix |
Reject |
Reference Values
No growth of Clostridioides difficile.
Susceptibility results are reported as minimal inhibitory concentration (MIC) in mcg/mL. Breakpoints (also known as clinical breakpoints) are used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, resistant, or nonsusceptible according to breakpoint setting organizations, either the Clinical and Laboratory Standards Institute (CLSI) or the European Committee on Antimicrobial Susceptibility Testing (EUCAST), as applicable.
In some instances, an interpretive category cannot be provided based on available data; therefore, the following comment will be included on the report: There are no established interpretive guidelines for agents reported without interpretations.
For information regarding CLSI and EUCAST susceptibility interpretations, see Susceptibility Interpretative Category Definitions.
Supportive Data
Fifty fecal specimens in Cary Blair transport media that were previously determined as positive for Clostridioides difficile by toxin PCR were subcultured directly onto CHROMagar C difficile plates. Plates were incubated under anaerobic conditions at 37° 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 to 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.
Metronidazole clinical breakpoints are interpreted according to Clinical and Laboratory Standards Institute (CLSI) guidelines. For C difficile, an epidemiological cutoff value (ECV) of less than or equal to 2 mcg/mL (wild-type) and greater than or equal to 4 mcg/mL (non-wild type) is applied for vancomycin, according to CLSI guidelines. If C difficile strains were to acquire a resistance gene or undergo gene mutation resulting in reduced susceptibility, vancomycin minimal inhibitory concentration (MIC) values of greater than or equal to 4 mcg/mL would be expected. When considering vancomycin therapy for C difficile infection, clinical breakpoints have not been established due to lack of sufficient data on clinical outcomes by MIC.(7,8) It is suggested that susceptibility testing of C difficile isolates and interpretation of results be discussed with appropriate clinical specialists (eg, infectious diseases and/or pharmacy).
Day(s) Performed
Monday through Sunday
Report Available
2 to 9 daysSpecimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
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)
87181-Anaerobe Susceptibility per agent (if appropriate)
87181 x 3-Antimicrobial Susceptibility, Anaerobic Bacteria, MIC (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CDIFS | C. difficile Culture + Susc | 105047-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CDIFS | C. difficile Culture + Susc | 105047-5 |