Veterinary practices today can enhance their parasite diagnostics by switching to fecal antigen testing, which improves both the scope and accuracy of fecal testing results. This testing method employs antibodies to detect specific proteins that are unique to certain organisms. The targeted protein is secreted or excreted by a parasite within the intestinal lumen of the infected animal, regardless of the parasite's egg production.

The fact that this method of testing does not require the identification of eggs is a crucial aspect of its efficacy as an accurate screening test for infected dogs or cats that are asymptomatic or may exhibit a range of clinical signs potentially associated with parasite infection.^1-3

The Antigen Study

All small animal veterinary practices recognize the importance of fecal screening for both canine and feline wellness, but there's significant variability in the age and frequency of the recommendations. The Companion Animal Parasite Council (CAPC) recommends conducting microscopic fecal exams at least four times during the first year of life and twice a year in adults.⁴ They also recognize that diagnostics and screening with advanced technologies, such as antigen tests, may be preferred.

A recent fecal antigen study demonstrated significant results supporting this CAPC guideline. In this retrospective study⁶, investigators compared fecal antigen testing and centrifugal flotation in 898,300 wellness testing samples. The samples were divided by age and species into six groups.

Within these age groups and species, all six antigen results were compared to any ova and parasite result from a standard fecal flotation test. The antigen test accurately screens for the most common and clinically relevant intestinal parasites, including roundworms, hookworms, whipworms, flea tapeworms, and Cystoisospora.⁵

Summary of Results

This vast retrospective study⁶ revealed several significant findings, including the following:

• Overall, fecal antigen testing alone detected up to twice as many infections compared to centrifugal flotation alone.
• Results were consistent across all age groups. While parasitism was identified more frequently in younger animals by both methods, parasitism is generally more common in younger age groups. Observing the number of parasites found by fecal antigen testing as pets age is more informative. They should be on routine monthly parasite prevention as well.
• Lastly, flotation rarely detects incremental, clinically relevant infections (0.2%–0.6% of all patients when common treatments are considered). However, fecal antigen testing was much more effective at identifying clinically relevant infections (9.4%) where treatment was indicated. As a clinician, this highlights the significant clinical information being missed during our patients' wellness exams.

What This Means for Veterinary Practices

In any study, it's crucial not only to understand the setup and results but also to know how to apply those findings to daily practice. Here, these discoveries can enhance the quality of fecal wellness and illness screening and diagnostic tests while contributing appropriate incremental revenue from the diagnostics profit center of your practice.

These study results indicate that fecal antigen testing alone can identify 11 additional clinically relevant parasite infections per veterinarian per month (or 141 per year) in patients who otherwise appeared healthy and would not have detectable infections using flotation alone.

Take a moment to absorb that statistic. Eleven additional clinically relevant infections each month means 11 patients with a disease requiring treatment are currently being overlooked. It also implies 11 more patients may remain contagious to other animals in the house or neighborhood or even to the humans in the home through zoonotic transfer. Furthermore, it emphasizes 11 more animals that need a more comprehensive discussion regarding their monthly parasite prevention strategy.

As veterinary practices continually strive to enhance the quality of their medicine through innovation and efficiency, fecal antigen testing can help achieve both with a single sample sent to the reference lab. It's this type of innovation that needs to be embraced today, replacing the traditional methods of the past, to improve diagnostic accuracy and disease prevention.

References:

1. 1. Elsemore DA, 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. https://pubmed.ncbi.nlm.nih.gov/37491878/.
   2. 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. https://pubmed.ncbi.nlm.nih.gov/24670954/.
   3. 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. https://pubmed.ncbi.nlm.nih.gov/28424002/.
   4. Companion Animal Parasite Council. General guidelines for dogs and cats. September 16, 2022. Accessed February 6, 2025. https://capcvet.org/guidelines/general-guidelines.
   5. Sweet S, Hegarty E, McCrann DJ, Coyne M, Kincaid D, Szlosek D. A 3-year retrospective analysis of canine intestinal parasites: fecal testing positivity by age, U.S. geographical region and reason for veterinary visit. Parasites and Vectors. 2021;14(1):173. DOI:10.1186/s13071-021-04678-6. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-021-04678-6
   6. 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.

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