Fig. 2From: Development and validation of an indirect ELISA as a confirmatory test for surveillance of infectious bovine rhinotracheitis in vaccinated herdsAnalytical sensitivity. Field sera a, b, and c were serially diluted with negative serum and tested with the blocking ELISA (black circles) and the rec-gE indirect ELISA (white circles). The gray area shows the window of uncertainty in the interpretation of the results for the blocking ELISA. The optimal cut-off for the rec-gE ELISA should be reevaluated (see Discussion)Back to article page