Abstract
Objective—To evaluate the performance of an in-clinic ELISA designed for detection of heartworm antigen and antibodies against 5 tick-borne pathogens.
Design—Validation study.
Sample—1,601 serum or matched serum, plasma, and blood samples from dogs.
Procedures—Samples were tested for Dirofilaria immitis (heartworm) antigen and antibodies against Anaplasma phagocytophilum, Anaplasma platys, Borrelia burgdorferi, Ehrlichia canis, and Ehrlichia ewingii by means of an in-clinic ELISA. Evaluation of assay sensitivity and specificity, agreement of results among sample types, and cross-reactivity of E canis antigens in the assay with anti–Ehrlichia chaffeensis antibodies in stored samples from experimentally infected dogs were performed at a reference laboratory. Field tests of the in-clinic ELISA were performed at 6 veterinary facilities. Results were compared with confirmatory test results.
Results—Sensitivity and specificity of the in-clinic ELISA were > 89% for detection of antibodies against A phagocytophilum (93.2% and 99.2%, respectively), A platys (89.2% and 99.2%, respectively), B burgdorferi (96.7% and 98.8%, respectively), E canis (97.8% and 92.3%, respectively), and E ewingii (96.5% and 93.9%, respectively). Sensitivity of the assay for detection of D immitis was 98.9%, with 99.3% specificity. The in-clinic ELISA identified exposure to > 1 vector-borne pathogen in 354 of 1,195 samples. Cross-reactivity of E canis antigens with anti–E chaffeensis antibodies was confirmed. Results of field evaluations confirmed that the in-clinic ELISA could be reliably used under typical clinical conditions to identify dogs exposed to the pathogens of interest.
Conclusions and Clinical Relevance—The in-clinic ELISA provided a comprehensive in-house serologic screening test for all vector-borne pathogens evaluated.
