Blood is one of the reagents on a standard urine dip stick test. And the range goes from negative through small, moderate and on to large.
However, any degree of blood in the urine is considered abnormal and should be further investigated by a veterinarian. The most common cause is a urinary tract infection which often responds quickly to treatment. Catching the condition in the early stages is critical, however.
Other causes of blood in the urine of your dog or cat can be due to the presence of a tumor, a perforation or even just a tough blade of grass that was eaten and scratched the lining of the digestive system.