Creatinine in cats is a chemical waste product that is produced by normal muscle metabolism. Creatinine is produced by creatine, which is the major energy source for muscles. Creatinine is filtered from the body by the kidneys; creatinine levels in a cat's blood are used to measure kidney function.
Normal creatinine levels
Because muscle mass in a cat's body remains fairly constant from day to day, the creatinine levels in the blood remain fairly constant as well. A normal creatinine for cats is .6 to 2.4 mg/dl.
Elevated Creatinine Levels
When a cat's kidneys are unable to flush out toxins at a normal rate, the creatinine level in the blood will be higher. Levels from 2.4 to 5.0 mg/dl are indicative of kidney disease; levels above 5.0 mg/dl signify complete kidney failure.
Your veterinarian will draw a blood sample from your cat and perform a serum blood panel. This test will measure the creatinine level as well as BUN (blood urea nitrogen), phosphorus, potassium and sodium levels. Your vet may also perform a urinalysis. The results of these tests will help determine the severity of the kidney disease and assist is designing treatment for your cat.
Many things can cause an elevated creatinine level in cats, including congenital diseases, abnormalities of the kidneys, hypertension, diabetes, certain medications, and toxins such as antifreeze. The most common reason for an elevated creatinine level in cats is age-related chronic kidney failure.
Depending on the reason that a cat's creatinine levels are elevated, treatment would include removing the toxin from the body, treating the underlying disease and flushing the kidneys with a large amount of intravenous fluids. If the cause of the elevated creatinine level is chronic kidney disease in your cat, there is no cure. The goal is to manage the animal's disease through diet and fluid therapy.
If the elevated creatinine levels are caused by toxins, and treatment is started immediately, your cat may recover. However, even with aggressive treatment, much of the time acute kidney disease is fatal. In cases of chronic kidney disease, the goal is to reduce the workload on your cat's kidneys. With a special diet and regular fluid therapy, your cat can live for many more months, or even years.