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. |