Tests for Clostridium difficile infection 7
| Test | Details |
|---|---|
| GDH EIA | GDH is a protein that is 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 PCR | This PCR test is specific for genes encoding toxins that are produced by C difficile, but a positive result does not help to 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 it is rarely performed in most clinical laboratories |
Given the variability of the sensitivity and specificity of these tests, a two-stage testing algorithm is widely applied. In the UK, toxin A/B enzyme immunoassay (EIA) testing is often used after an initial glutamate dehydrogenase (GDH) or polymerase chain reaction (PCR) screen7