The utility of coproantigen testing in screening populations

Detection of intestinal parasites is essential for veterinarians to assess risk of parasite infections. Traditionally, detection of intestinal parasites has relied primarily on detection of ova with fecal flotation methods. The purpose of this study was to evaluate the clinical utility of a commercially available coproantigen immunoassay detecting roundworms, hookworms, whipworms, Dipylidium caninum, Giardia and Cystoisospora spp. for detecting GI parasite infections in dogs and cats. The study evaluated test positivity of coproantigen and centrifugal fecal flotation and how often fecal flotation results would lead to clinical management changes compared to the result on coproantigen. Results for 898,299 samples submitted to a commercial reference laboratory (IDEXX Laboratories) over the three-month period from March 6, 2024, through June 6, 2024, with paired results for coproantigen immunoassay and centrifugal fecal flotation (O&P) were used for analysis. 83.7 % of samples were negative by both coproantigen and O&P. 6.1 % were positive on both methods and would result in the same treatment indicated. An additional 9.4 % of samples had a positive coproantigen result indicating a need for treatment but had no parasite detected by O&P. Finally, when samples with evidence of coprophagy are excluded, only 0.6 % of samples had a positive O&P result but were negative for all coproantigens. Coproantigen was more effective at identifying dogs and cats where antiparasitic management was needed than O&P. The results of this study support the use of coproantigen immunoassay testing as a highly accurate and effective screening method for intestinal parasitism.