Gastrointestinal protein loss can be challenging to diagnose.
Serum and fecal canine α1PI reflect the severity of intestinal crypt abscesses/lacteal dilation.
Fecal canine α1PI is superior to serum canine α1PI for diagnosing GI protein loss.
The serum/fecal canine α1PI ratio has an improved accuracy in hypoalbuminemic dogs.