Fecal Dx antigen testing
Algorithm for fecal screening on sick dogs
Testing recommendations vary based on the duration and severity of diarrhea and the health and dietary habits of the dog or dogs affected.
In simple diarrhea cases of short duration, a Giardia antigen by ELISA or the SNAP Giardia Test is recommended in addition to Fecal Dx antigen testing and fecal flotation by centrifugation. A more comprehensive diarrhea RealPCR panel is recommended in complicated diarrhea cases.

Simple diarrhea versus complicated diarrhea
Simple diarrhea
- Otherwise clinically healthy and bright, alert, and responsive (BAR)
- Mild diarrhea <24 hours in duration
- Only one dog affected
- +/– history of dietary indiscretion or recent diet change
Complicated diarrhea
- Clinically sick dog (lethargy, inappetance)
- Severe or hemorrhagic diarrhea
- Recurrent or persistent diarrhea
- Multiple animals affected
Use the following algorithm to rule out infectious diseases by differentiating between simple and complicated diarrhea and testing accordingly.
Simple diarrhea
- Otherwise clinically healthy and bright, alert, and responsive (BAR)
- Mild diarrhea <24 hours in duration
- Only one dog affected
- +/– history of dietary indiscretion or recent diet change
If negative or if diarrhea persists despite targeted therapy, evaluate for primary or concurrent noninfectious causes. Consider:
Dietary trials (high fiber or novel protein/hypoallergenic)
Cobalamin (vitamin B12), folate, TLI, Spec cPL Test
Abdominal ultrasound
Endoscopic or surgical intestinal biopsies
Complicated diarrhea
- Clinically sick dog (lethargy, inappetance)
- Severe or hemorrhagic diarrhea
- Recurrent or persistent diarrhea
- Multiple animals affected
If negative or if diarrhea persists despite targeted therapy, evaluate for primary or concurrent noninfectious causes. Consider:
Dietary trials (high fiber or novel protein/hypoallergenic)
Cobalamin (vitamin B12), folate, TLI, Spec cPL Test
Abdominal ultrasound
Endoscopic or surgical intestinal biopsies
Testing "healthy" dogs
In seemingly healthy adult dogs, flotation by centrifugation misses half of the most common parasites.1
Talk with your clients
Help your pet owners be proactive about regular parasite screening. Get resources to increase client compliance and reduce the spread of infection.
Reference
- Data on file at IDEXX Laboratories, Inc. Westbrook, Maine USA.