Routine hematologic and biochemical findings often are unremarkable in dogs and cats with congenital PSSs. Hematologic findings include microcytosis, target cells, poikilocytosis, and mild nonregenerative anemia. Isosthenuria or hyposthenuria frequently is detected. Ammonium biurate crystals are a common finding on urine sediment examination. Coagulation tests in dogs may show increased PTT and hypofibrinogenernia.
Hepatocellular dysfunction is suggested by hypoproteinemia, hypoalbuminemia, hypoglobulinemia.
Total serum bilirubin concentration typically is normal. Serum liver enzyme activity is normal to mildly increased, consistent with a lesion of hepatic atrophy. Fasting SBA concentrations often are increased but can be normal. Postprandial concentrations are consistently abnormal and are a good screening test for animals suspected to have PSSs. Microhepatica, a common finding of dogs with congenital PSSs, is a less consistent finding in cats.