Comparison of gastrointestinal parasite detection methods in fecal samples from dogs and cats in the United States: qPCR, coproantigen immunoassays, and centrifugal flotation

Abstract Background Gastrointestinal parasitism is prevalent among domestic dogs and cats in North America and represents a significant cause of clinical disease, particularly in puppies and kittens. The detection and correct identification of parasites in feces currently relies primarily on three different laboratory principles. This field evaluation study aimed to assess the diagnostic performance of a qPCR panel in comparison with coproantigens and conventional zinc sulfate centrifugal flotation (O&P) for the detection of gastrointestinal parasites. Methods A convenience set of 1013 fecal samples from dogs and cats were collected in May and June 2025. Each sample from this study was evaluated with three different tests used to diagnose parasitic infections in dogs and cats: qPCR panel, coproantigen tests, and O&P. Each of the three platforms was systematically evaluated against every other platform in a pairwise manner. Each sample was also coded as “parasite detected” or “parasites not detected” for overall parasite detection between the three tests. Results Overall, the qPCR panel, coproantigens, and O&P detected parasitic targets in 276, 110, and 66 samples, respectively. Parasitic targets were detected in 29.62% of samples by the three diagnostic platforms. The qPCR panel detected twice as many parasitic targets than the coproantigens and O&P combined. The qPCR panel detected four times more parasitic targets as the O&P. When comparing the 6 parasitic targets detected by the coproantigen tests to the qPCR tests, qPCR detected 1.6 more parasitic targets. Overall, the 20 qPCR tests detected 3.8 times more parasitic co-infections compared to the coproantigens and O&P tests combined. Conclusions The qPCR panel demonstrated a higher detection rate for parasites when compared to the coproantigen tests and traditional O&P methods irrespective of the parasitic taxa, indicating its utility as a screening method for intestinal parasitism in dogs and cats.