Assessing the effect of sample handling on the performance of a commercial bovine viral diarrhea virus antigen-capture enzyme-linked immunosorbent assay

Handling practices of specimens may affect the sensitivity or specificity of diagnostic tests. In this study, as part of the Voluntary Iowa Bovine Viral Diarrhea Virus Screening Project held in 2006, 2 sample-handling practices were evaluated to determine how they affect the sensitivity and specificity of the antigen-capture enzyme-linked immunosorbent assay (ACE) for bovine viral diarrhea virus (BVDV). The null hypotheses investigated were 1) that maintenance of samples at room temperature would not be associated with decreased sensitivity, and 2) that continued use of a single pair of ear notchers would not be associated with cross-contamination of virus from 1 notch to another and reduce specificity. These hypotheses were tested in 2 studies by collecting known positive and negative samples and giving groups of samples different treatments. The first study used ACE on 4 groups of skin samples, all from a known-positive animal. Each group was subjected to different lengths of time at room temperature, from 24 to 96 hours at 24-hour intervals. No difference in test results was found between specimens subjected to different lengths of time at room temperature. The second study tested the effects of giving 3 different treatments to an ear notcher in between sample collecting (water rinse, Nolvasan solution rinse, or no treatment) on ACE results. No effect on sensitivity or specificity of ACE was observed. No difference in test results was found between the 3 ear-notcher treatment groups. The sample handling practices evaluated appeared to have little impact on test sensitivity or specificity of ACE for BVDV.