The Creatinine Level Of Your Dog And Cat’s Urine And Why It Is Important

Ron Hines DVM PhD

To see what normal blood and urine values are, go here

For an explanation of causes of most abnormal blood and urine tests, go here

To see how tests are grouped, go here

About The Creatinine In Your Dog And Cat’s Urine

The creatinine in your dog and cat’s urine, as well as in your urine, originates from the same sources (chiefly a byproduct of muscle metabolism – with some contribution from the animal proteins we may eat). The same creatinine first circulates in the blood. It is the kidney’s job to filter it out . (ref

The presence of creatinine in your pet’s urine does not, in itself, tell your veterinarian very much. When dogs and cats are not eating, urine creatinine level can be low. (ref) Its chief value is that unlike many other urine components (such as water, cortisol and protein) normal kidneys excrete creatinine at a rather constant rate throughout the day. So the creatinine level in your pet’s urine is often compared to other urine constituents to decide if those other constituent levels are higher or lower than they ought to be. Creatinine can be used as a standard benchmark or used in a ratio to which other urine components are compared. Those other components tend to fluctuate more with changes in your pet’s urine concentration throughout the day rather than give an accurate estimate of their average blood values. Several urine assays – like urine cortisol:creatinine ratio, a rule-out test for Cushing’s disease (or for illegal drug screening in humans) rely on this rather steady rate of creatinine urinary excretion.

When your veterinarian is attempting to evaluate the condition of your dog or cat’s kidneys, he/she is considerably more likely to examine your pet’s blood creatinine level than its urine creatinine level and to look at other urine parameters like specific gravity or albumen content.

Pets receiving certain antibiotics (eg cephalosporins, gentamicin, trimethoprim-sulfa) or antacids (such as cimetidine) can give incorrect urine creatinine and creatinine ratios.

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