Clostridioides difficile Toxins A and B, EIA

CPT: 87324
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  • Antibiotic-associated Colitis Toxin Test
  • Pseudomembranous Colitis Toxin Assay

Test Includes

Immunoassay for Clostridium difficile toxins A and B. Requests with only a written order and no test number indicated will be processed according to Default Testing for Routine Microbiology.

Special Instructions

A separate specimen is required for culture or for the toxin B cytotoxin assay.

Expected Turnaround Time

1 - 2 days

Related Documents

For more information, please view the literature below.

Microbiology Specimen Collection and Transport Guide

Specimen Requirements




5 g

Minimum Volume

0.5 g or 0.5 mL liquid stool


Sterile screw-cap container or stool transport (Para-Pak® white clean vial), no preservative. “Cool Whip” containers, denture cups, or other similar containers often leak or even explode during transport and may be rejected by the laboratory.

Storage Instructions

Specimen should be kept refrigerated and transported to the laboratory within 24 hours of collection. If a longer period is required, the specimen should be frozen at -20°C or lower.

Stability Requirements




Up to 72 hours from collection (stability provided by manufacturer or literature reference)


After 72 hours (stability provided by manufacturer or literature reference)

Causes for Rejection

Specimens from patients less than two years of age; inappropriate specimen transport conditions (eg, room temperature) or transport device; unlabeled specimen or name discrepancy between specimen and request label; specimen received after prolonged delay (usually more than 72 hours); specimens other than stool; leaking specimen; specimen received in denture cup, "Cool Whip" container, margarine container, or similar container

Test Details


Aid in the diagnosis of antibiotic-associated diarrheal disease and pseudomembranous colitis


Detection of toxins A and B by enzyme immunoassay has a sensitivity approaching 90%, so multiple specimens may need to be tested. Performance characteristics have not been established in a pediatric population.


Enzyme immunoassay (EIA) for Clostridium difficile toxins A and B

Additional Information

C difficile can produce two toxins, designated A and B, that have pathogenic effects in humans. Antibiotic-associated pseudomembranous colitis has been shown to result from the action of these two toxins. This disease has been associated with clindamycin use but it is now recognized that pseudomembranous colitis can follow administration of virtually any antibiotic. More than 70% of the cases in a large series were associated with cephalosporin therapy.1 The clinical spectrum of antibiotic-induced syndromes caused by C difficile includes patients with symptoms of acute abdomen with little or no diarrhea, as well as cases with fulminant life-threatening diarrhea. Nosocomial transmission and reinfection with different strains occurs as do spontaneous cases without prior antimicrobial therapy. In cases where cessation of antibiotic therapy does not produce a response, specific therapy with oral vancomycin, metronidazole, or oral bacitracin may be effective. Detection of the toxins produced by C difficile (rather than culture of the organism) is important in the determining therapy of this potentially fatal disease. The routine use of culture does not seem appropriate because of the costs and the high rate of recovery of strains which do not produce toxin.


1. Talbot RW, Walker RC, Beart RW Jr. Changing epidemiology, diagnosis and treatment of Clostridium difficile toxin-associated colitis. Br J Surg. 1986 Jun; 73(6):457-460. 3719271


Bartlett JG. Antibiotic-associated colitis. Dis Mon. 1984 Dec; 30(15):1-54. 6391879
Gerding DN. Disease associated with Clostridium difficile infection. Ann Intern Med. 1989 Feb 15; 110(4):255-257. 2643913
Gerding DN, Olson MM, Peterson LR, et al. Clostridium difficile-associated diarrhea and colitis in adults. A prospective case-controlled epidemiologic study. Arch Intern Med. 1986 Jan; 146(1):95-100. 3942469
Lyerly DM, Krivan HC, Wilkins TD. Clostridium difficile: Its disease and toxins. Clin Microbiol Rev. 1988 Jan; 1(1):1-18. 3144429
McFarland LV, Mulligan ME, Kwok RY, Stamm WE. Nosocomial acquisition of Clostridium difficile infection. N Engl J Med. 1989 Jan 26; 320(4):204-210. 2911306


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
086207 C difficile Toxins A+B, EIA 34468-9 182238 C difficile Toxins A+B, EIA 34468-9

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