Blood testing is done to check for any of the following: BUN/Creatinine/SDMA-The BUN (blood urea nitrogen) is one of 3 blood tests for kidney function. It is a good screening test but not a perfect test, as it requires destruction of 60-70% of kidney function before it elevates significantly.
Creatinine refers to an amino acid constituent of muscle protein that also requires destruction of 60-70% of kidney function before it elevates significantly due to decreased filtering by the damaged kidneys. It is also affected by diet, exercise, and muscle mass, so results can be skewed due to non-kidney factors (but not as much as the BUN.) Other tests which can help prognose pets with kidney failure include blood levels of phosphorus and calcium. Phosphorus especially tells us the severity of kidney issues as it elevates when the kidneys are severely damaged. Pets with elevated blood phosphorus levels AND elevated levels of the kidney enzymes just mentioned are much harder to treat and have a poorer prognosis.
Urine testing can be done using a urinalysis and urine culture, that give us additional information the blood testing may not give us. Keep in mind that many pets have early protein (albumin) loss through the kidneys detected in a urinalysis (not detected in a blood profile; excessive urine protein loss is very common in dogs and requires early treatment to prevent more serious problems.) Additionally, a urine culture is needed anytime an infection is suspected to allow us to properly diagnose and treat this common pet problem.
Finally, radiographs or ultrasound may be needed to look for cysts, tumors, stones, and congenital problems that also commonly occur in dogs and cats. Following proper testing, we utilize many therapies, mostly natural, to help these special patients return to a normal life quickly.