Quantitation of canine plasma von Willebrand factor antigen using a commercial enzyme-linked immunosorbent assay.
The purpose of this study was to evaluate a commercial enzyme-linked immunosorbent assay (ELISA) for human von Willebrand factor antigen (vWF:Ag) with respect to its potential value in quantitating the protein in canine plasma. The assay was a sandwich technique using F(ab')2 fragments specific for von Willebrand factor (vWF) and a peroxidase conjugated rabbit anti-vWF second antibody, with a microplate as the support surface. Canine plasmas were assayed by ELISA, and by Laurell electroimmunoassay (EIA), our reference methodology. The ELISA had a within-day variation of 1.21-4.44% and a between-day variation of 0.85-4.88% depending on the level of vWF:Ag. The sensitivity of the assay was less than 0.1% vWF:Ag. The range of vWF:Ag concentrations in plasmas from 24 clinically normal dogs compared favorably with the range for the same plasmas when assayed by EIA (ELISA = 60-152% of normal; EIA = 50-142% of normal). In 121 canine plasmas with vWF:Ag concentrations (as assessed by EIA) ranging from undetectable levels (less than 6% of normal) to 142% of normal, there was good correlation with measurements made by ELISA (correlation coefficient = 0.835). It was concluded that this commercial ELISA technique could be used to provide reliable, same-day measurements of canine plasma vWF:Ag. Since it requires no special equipment other than a microplate reader and washer it is particularly suitable for laboratories lacking the electrophoretic expertise or equipment required for EIA.
Johnstone
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Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Ontario.
Crane
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D000818:Animals; D004285:Dogs / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D007124:Immunoenzyme Techniques; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic / Q000662:veterinary; D012016:Reference Values; D015203:Reproducibility of Results; D014841:von Willebrand Factor / Q000032:analysis*
D011933:Reagent Kits, Diagnostic; D014841:von Willebrand Factor