Ammonia tolerance test in clinically normal dogs and in dogs with portosystemic shunts

The oral ammonia tolerance test was investigated in 20 clinically normal dogs and in 6 dogs with naturally occurring portosystemic shunts. The dogs with portosystemic shunting had a marked rise in venous blood ammonia following the administration of ammonium chloride, as compared with the control dogs. Fasting venous blood ammonia content was not uniformly reliable in separating the dogs with portosystemic shunting from the clinically normal dogs.