Evaluation of four commercially available enzyme immunoassays for laboratory diagnosis of Clostridium difficile-associated diseases.
Four commercial enzyme immunoassays (EIAs) for the detection of Clostridium difficile toxin A have recently been developed and marketed (Premier, Meridian Diagnostics, Cincinnati, Ohio; VIDAS, bioMerierux Vitek, Inc., Hazelwood, Mo.; Tox-A-Test, TechLab, Blacksburg, Va.; and Bartels, Baxter Diagnostics, McGaw Park, Ill.). The performances of these EIAs were compared with those of the tissue culture cytotoxicity assay and a definition of C. difficile-associated disease based on both laboratory and clinical criteria for 329 clinical specimens. Two EIAs (Premier and VIDAS) showed good overall agreement (96 and 95%, respectively) with the cytotoxicity assay. However, they were less sensitive (84 and 71%, respectively) than the Bartels (94%) or Tox-A-Test (93%) EIAs. The Bartels and Tox-A-Test assays were much less specific, resulting in poor positive predictive values (56%) of the two assays when compared with that of the cytotoxicity assay. Tox-A-Test had the added drawback of having a significant number of indeterminate results (6.4%). These data indicate that the four EIAs all have specific shortcomings. When using these EIAs, testing strategies that take these shortcomings into consideration should be developed.
Whittier
S
S
Clinical Microbiology Laboratory, University of North Carolina Hospitals, Chapel Hill 27599.
Shapiro
D S
DS
Kelly
W F
WF
Walden
T P
TP
Wait
K J
KJ
McMillon
L T
LT
Gilligan
P H
PH
D000328:Adult; D001427:Bacterial Toxins / Q000032:analysis*; D002648:Child; D016360:Clostridioides difficile / Q000472:pathogenicity*; D003365:Costs and Cost Analysis; D046508:Culture Techniques; D003967:Diarrhea / Q000382:microbiology*; D004768:Enterotoxins / Q000032:analysis*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000191:economics
D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile