ELISA test that detects two specific antigens (A and C). Results ≤ 0.2 for both antigens are considered negative and indicate that the animal is unlikely to have been exposed to S. equi 2 weeks prior to sampling or be a carrier. Results 0.3 to 0.4 for either antigen are considered suspect and indicate that recent exposure to S.equi may have occurred. Results ≥ 0.5 for either antigen are considered positive and should be confirmed with additional PCR or culture on a nasopharyngeal swab and guttural pouch wash.