C.diff EIA

anti_bio

Performance of the TechLab C. DIFF CHEK-60 Enzyme Immunoassay (EIA) in Combination with the C. difficile Tox A/B II EIA Kit, the Triage C. difficile Panel Immunoassay, and a Cytotoxin Assay for Diagnosis of Clostridium difficile-Associated Diarrhea
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC522321/

anti_bio

Diagn Microbiol Infect Dis. 2007 Sep;59(1):33-7. Epub 2007 Jul 26.
Performance of TechLab C. DIFF QUIK CHEK and TechLab C. DIFFICILE TOX A/B II for the detection of Clostridium difficile in stool samples.
Reyes RC, John MA, Ayotte DL, Covacich A, Milburn S, Hussain Z.
SourceDepartment of Medical Microbiology, London Health Sciences Centre, Victoria Hospital, London, Ontario, Canada N6C 6B5.

Abstract
Two membrane-bound enzyme immunoassays by TechLab, Blacksburg, VA, were evaluated and compared with the Triage Micro C. difficile Panel (Biosite Diagnostics, San Diego, CA), with culture, and with cytotoxic assay. The TechLab panels were C. DIFF QUIK CHEK (QC-GDH) and C. DIFFICILE TOX A/B II (QC-toxinA/B), which detect glutamate dehydrogenase (GDH) and Clostridium difficile toxins A and B, respectively. The Triage Panel detects GDH (TR-GDH) and toxin A (TR-toxinA).

METHODS: Stool samples were inoculated onto CCFA plates (Q-Labs, Quebec, Canada) after alcohol shock, and suspected colonies were identified by the MicroScreen C. difficile latex slide agglutination test (Microgen Bioproducts, Surrey, UK). TR-GDH, TR-toxinA, QC-GDH, and QC-toxinA/B tests were performed according to the manufacturers' instructions on all the samples. Samples positive for GDH or culture but negative for TR-toxinA and QC-toxinA/B were further tested by cytotoxin assay (CTA). CTA was also performed on samples that caused blackening of the Triage Micro C. difficile Panel.

RESULTS: A total of 313 of 401 stool samples were negative for GDH and toxins (78%). Eighty-eight samples were positive either for GDH or culture or both. Thirteen of these could not be evaluated for C. difficile-associated diarrhea (CDAD) because CTA test was not performed. Toxin/s was detected at least by one method in 46 (11.8%) of 388 samples that were positive for culture or GDH and were considered diagnostic of CDAD. The QC-GDH was more sensitive than culture and TR-GDH for the detection of C. difficile. However, in 18GDH-positive samples positive for either of the Triage or TechLab immunoassays, the culture remained negative. Ten (2%) results of the Triage immunoassays could not be evaluated because of discoloration of the panels. QC-GDH (93.5%) was more sensitive for detecting the presence of toxin-producing C. difficile than TR-GDH (79.5%). TR-toxinA was more specific for detecting the presence of toxin-producing C. difficile than QC-toxinA/B (100% and 96.9%, respectively).

CONCLUSIONS: The GDH tests had a faster turnaround time than the traditional culture methods. QC-GDH was most sensitive for the detection C. difficile-positive stools and was easy to use.