The Evolution of Fecal Testing in Veterinary Medicine: Where it Started and What's Coming
Fecal testing in veterinary medicine has significantly evolved over the past few decades. The standard of care for detecting fecal ova and parasites was established in the mid-1900s when centrifugal flotation techniques improved the recovery of ova compared to passive flotation. However, many practitioners have now transitioned from centrifugation to antigen testing as the preferred method for patient screening.
Additionally, the Companion Animal Parasite Council (CAPC) has recognized the importance of antigen testing. As we reflect on the evolution of fecal testing, technological advancements have significantly improved accuracy, enabled multi-pathogen detection from a single test, enhanced operational efficiency, and facilitated the detection of rare or emerging pathogens.
Fecal Testing's Origins
The standard centrifugal fecal flotation technique was developed in the mid-1900s when solutions containing sugar and zinc sulfate were found to concentrate parasite eggs, increasing the number of ova visualized under the microscope. While this technique remained popular, fecal sedimentation and staining methods were introduced in the late 1900s. This sedimentation approach aided in detecting heavier parasite eggs (such as trematodes). Staining techniques, like acid-fast stains, were utilized to help identify Cryptosporidium and other protozoa.
In the early 2000s, significant advancements were made in commercial diagnostic kits and automation. This included popular point-of-care fecal antigen tests introduced for Giardia as well as automated fecal analysis machines that began operating to improve efficiency and standardization within practices. Since its introduction, the use of fecal antigen testing has steadily increased. It has now become a commonly accepted test of choice, detecting the most prevalent parasites: Giardia, whipworms, tapeworms, Cystoisospora, hookworms, and roundworms.
In the 2010s, molecular diagnostics and PCR testing became increasingly popular for detecting specific pathogens such as parvovirus, Tritrichomonas, and Giardia. This technology enabled the creation of multiplex PCR panels, allowing for simultaneous testing of multiple pathogens with greater accuracy.
The Evidence Behind the Switch to Fecal Antigen Testing
The release of new technology for fecal screening has been accompanied by several studies examining the accuracy and benefits of fecal antigen testing compared to standard fecal flotation.1-3 A false negative means the patient remains infected and untreated, allowing for continued shedding and contamination of the environment. This increases zoonotic risks and places both the family and the practice at potential risk of litigation.
An impressive study by IDEXX compared fecal antigen testing and centrifugal flotation in 898,300 samples, with any of the six antigen results compared to a standard fecal ova and parasite centrifugation result.4 Overall, fecal antigen testing alone identified up to two times more infections than centrifugal flotation alone, with results consistent across age groups. Moreover, flotation rarely detected any clinically relevant incremental infections (0.2%-0.6% of all patients when common treatments were considered).
Future Trends in Fecal Disease Screening
As we look to the present and future of fecal disease screening, a few trends are leading the charge. First, it's encouraging to see that the CAPC recommendations for more frequent and consistent fecal testing is being followed. Veterinarians have increased their annual or semiannual fecal screening recommendation including for pets of all ages. Historically, some patients fell through the cracks in fecal screening, including shelter pets that had a previous fecal float performed, dogs from breeders, and many, if not all, indoor cats. Now, with strong support from the CAPC, there is a push for consistent semiannual fecal antigen screening of all dogs and cats, including shelter pets.
With an increase in fecal testing, and more specifically fecal antigen testing, we are able to have access to more clinical data for our patient as compared to the number of false negatives with standard fecal flotations. This data helps underscore the decisions we make for our patients on the right testing and treatment protocols when it comes to fecal testing.
Ultimately, the millennial demographic, as the largest group of pet parents, has cultivated a new culture of pet parent education concerning all veterinary services. They also desire to be more proactive and engaged in home care. We are seeing pet owners seek deeper insights into the value of diagnostics and display heightened interest in wellness screenings. This creates a fantastic opportunity to refresh or enhance your practice's wellness strategies, ensuring that fecal antigen screening is integrated and recommended by all team members. They are also increasingly interested and likely to request at-home fecal testing kits connected to telemedicine platforms. This is a very emerging area within the diagnostics field, and it will be thrilling to witness how this business strategy evolves.
References
- Elsemore D, Bezold T, Geng J, Hanna R, Tyrrell P, Beall M. Immunoassay for detection of Dipylidium caninum coproantigen in dogs and cats. J Vet Diagn Invest. 2023;35(6):671–678. doi:10.1177/10406387231189193
- Elsemore DA, Geng J, Flynn L, Cruthers L, Lucio-Forster A, Bowman DD. Enzyme-linked immunosorbent assay for coproantigen detection of Trichuris vulpis in dogs. J Vet Diagn Invest. 2014;26(3):404–411. doi:10.1177/1040638714528500
- Elsemore DA, Geng J, Cote J, Hanna R, Lucio-Forster A, Bowman DD. Enzyme-linked immunosorbent assays for coproantigen detection of Ancylostoma caninum and Toxocara canis in dogs and Toxocara cati in cats. J Vet Diagn Invest. 2017;29(5):645–653. doi:10.1177/1040638717706098
- Burton KW, Michael H, Drake C. The utility of coproantigen testing in screening populations. Vet Parasitol. Published online April 4, 2025. doi:10.1016/j.vetpar.2025.110459
