What is Creatinine?
A waste product removed by the kidneys, measured in blood to evaluate kidney function; elevated levels usually indicate that the kidneys are not filtering properly.
Creatinine is a breakdown product of creatine, a substance present in muscles, and is normally filtered out of the blood and eliminated by the kidneys in urine at a relatively constant rate. Because of this, measuring the amount of creatinine in the blood is one of the most common ways to indirectly evaluate kidney function: when the kidneys lose part of their filtering capacity, creatinine builds up in the blood and its levels rise.
An important detail is that creatinine usually only rises noticeably once a significant portion of kidney function has already been lost — that is why additional tests (such as SDMA, which is more sensitive for detecting early kidney function loss, and a urinalysis) help identify problems earlier. Elevated creatinine can indicate anything from temporary dehydration to chronic kidney disease, acute kidney injury (for example, from a toxin or urinary obstruction), or leptospirosis.
As with other blood tests, the creatinine value needs to be interpreted within the pet's clinical context and compared with previous results, when available, to evaluate trends over time. Senior pets, especially cats, should have their kidney function evaluated regularly, since chronic kidney disease is one of the most common conditions at this stage of life and tends to progress silently before symptoms appear.
Important notice
This calculator is for educational purposes and does not replace a veterinary evaluation. When in doubt, consult a veterinarian.Related terms
BUN (Blood Urea Nitrogen)
A substance produced by the liver from the breakdown of protein and eliminated by the kidneys; measured together with creatinine to evaluate kidney function.
Chronic Kidney Disease (CKD)
A progressive, irreversible loss of kidney function, very common in senior dogs and cats, that requires ongoing management to control symptoms and slow its progression.
Complete Blood Count (CBC)
A blood test that evaluates red blood cells, white blood cells, and platelets, used to investigate anemia, infection, inflammation, and clotting problems.