What Tests Are Needed For Cats with Kidney Disease?

If you've spotted the symptoms for what you think is kidney failure, bring your cat to your vet right away.

Your vet will likely run a Complete Blood Count to confirm whether or not your cat has kidney failure. He will draw some blood from a vein in your cat's neck using a needle and syringe. Once they have a sample, they will run the following tests:

Blood Urea Nitrogen (BUN) – which measures the level of a waste product excreted by the kidneys. Normal BUN levels are between 14 – 36 mg/dl.

Creatinine – is another waste product excreted through by the kidneys that is thought to indicate overall kidney function. Normal levels: .6 – 2.4 mg/dl.

Calcium – healthy cats have a calcium-to-phosphorus ratio of 1:1 to 2:1. If your cat's kidneys are not functioning properly, blood tests will indicate a rise in the levels of calcium. Normal levels: 8.2 – 10.8 mg/dl.

Phosphorus – cats with kidney failure have higher levels of phosphorus in their blood because their kidneys can no longer excrete it as efficiently. This excess phosphorus can make their condition worse. As you'll see when we get to special diets for cats with kidney failure, a low-phosphorus diet is crucial. Normal reading for phosphorus: 2.4 – 8.2 mg/dl.

These are the main blood tests for kidney disease. When BUN and creatinine are elevated, there's a good chance your cat's kidneys are compromised.

In addition, some vets may check for elevated levels of an enzyme called Amylase, which may be a warning signal of kidney disease. He may check cholesterol levels, which can increase with kidney disease. He may check Potassium levels which can be dangerously low, because of more frequent urination or vomiting in a sick cat. Some cats with kidney problems need potassium supplements to raise their levels. And your vet may check sodium levels, which can rise, since your cat is unable to excrete it. Too much sodium can lead to high blood pressure.

You will receive a detailed printout of you cat's blood tests. More importantly, you should have a consultation with the vet about what the numbers mean, and what to do next.