2.3. Blood and urine sample collection and processing

For control cats identified at the animal control facility, blood and urine samples were collected via cardiocentesis and cystocentesis, respectively, immediately after euthanasia with pentobarbital. For purpose‐bred control cats, blood and urine samples were collected via jugular venipuncture and cystocentesis, respectively, after sedation with intramuscular buprenorphine (0.03 mg/kg), acepromazine (0.1 mg/kg), and midazolam (0.3 mg/kg), immediately before euthanasia with pentobarbital. Serum, ethylenediaminetetraacetic acid‐anticoagulated blood, and urine samples were submitted for analysis within 1 hour of collection.

Client‐owned cats enrolled in the CKD group did not undergo blood and urine sampling. Information pertaining to each cat's renal function was obtained from review of the individual's medical record.