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. Author manuscript; available in PMC: 2019 Jan 23.
Published in final edited form as: Clin Med (Lond). 2018 Jun;18(3):237–241. doi: 10.7861/clinmedicine.18-3-237

Table 2. Tests available for Clostridium difficile infection.

Given the variability of sensitivity and specificity of these tests, a two-stage testing algorithm is widely-applied. In the UK, toxin A/B EIA testing is combined with GDH or PCR testing as the initial screen7.

Test Details
Glutamate dehydrogenase (GDH) enzyme immunoassay (EIA) GDH is a protein present in all isolates of C. difficile. This test is sensitive, quick and relatively cheap, but lacks high specificity for toxigenic forms of C. difficile. It is therefore often used as an initial screening test.
Toxin A and B EIA This test has high specificity but variable degrees of sensitivity.
Toxin A and B polymerase chain reaction (PCR) Whilst the PCR test is specific for genes encoding toxins produced by C. difficile, a positive result does not help distinguish active toxin production from asymptomatic carriage of toxigenic C. difficile.
Cell culture cytotoxicity assay This is still widely-recognised as the reference standard test, although is rarely performed in most clinical laboratories.