What Do Kidney Numbers Mean in Dogs?

Kidney function values are found in his blood and urine samples.
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If you have been refilling your dog’s water bowl more frequently and letting him outside more often to relieve himself, then a visit to the veterinarian is in order. These can be symptoms of kidney disease, Cushing’s disease or diabetes. The first thing your veterinarian will do is collect blood and urine samples for testing. If the diagnosis is kidney disease, several key values exist in the test results that your vet will watch for.

Urine Specific Gravity and Albumin

Kidneys that function normally remove waste from the bloodstream to be expelled in urine while retaining as much water in the body as possible to maintain hydration. The result is concentrated urine. Poor kidney function cannot concentrate the urine, which is why your dog must drink more water in an attempt to excrete the excess toxin load. This leads to dilute urine. Your veterinarian is interested in the urine specific gravity to determine how efficiently the kidneys are concentrating your dog’s urine. The normal specific gravity range for a dog is 1.015 to 1.050. A lower specific gravity value indicates poor kidney function. The other urine value to observe is the albumin level. This represents the level of blood proteins that have leaked from the deteriorating kidneys into the urine. The normal range is 2.7 to 4.4, and a higher value indicates kidney disease.

Blood Urea Nitrogen and Creatinine

Two key kidney values in your dog’s blood chemistry are the blood urea nitrogen and the creatinine levels. Blood urea nitrogen and creatinine are both metabolic protein wastes that the kidneys filter from the blood. When the kidneys can no longer keep up with their filtration duties, the levels of these wastes rise. A normal blood urea nitrogen range for dogs is 6 to 25, and the normal range for creatinine is 0.5 and 1.6. Higher values indicate failing kidney function. When the creatinine level nears 5.0, you dog will feel sick and may show such symptoms as vomiting, fatigue and decreased appetite. At this stage, 80 to 90 percent of his kidneys have been destroyed.

Blood Phosphorus and Potassium

Phosphorus, a mineral component found in the blood, works in tandem with your dog’s calcium to maintain strong bones. Too much phosphorus creates an imbalance of the two minerals, so the kidneys must excrete just enough phosphorus to maintain a healthy phosphorus-to-calcium ratio. A normal phosphorus level is 2.8 to 6.2. When your dog’s phosphorus value exceeds this range, his bones will start to weaken. Potassium is an important mineral and electrolyte responsible for maintaining your dog’s heart function and overall well being. The ideal range is 3.6 to 5.5. In early stage kidney disease, potassium levels tend to be elevated, resulting in a condition called hyperkalemia. In the advanced stage, the potassium level falls dangerously low, resulting in hypokalemia.

Values Must Be Tracked

When your veterinarian has confirmed a diagnosis of kidney disease, he will discuss treatment options. To place less stress on the wearing kidneys, your veterinarian may prescribe a diet that is low in protein, sodium and phosphorus. He might prescribe medications to help maintain your dog’s present values, and suggest fluid therapy to help keep your dog hydrated. Your vet will run periodic blood chemistry panels and urinalyses to track the kidney values so adjustments in treatment may be made to address any changes as they arise. He may also monitor your dog’s blood pressure, which can elevate as a result of kidney disease. Kidney disease is a degenerative condition, meaning that there is no cure. The goal of treatment is to slow the progression of the disease and preserve your companion’s quality of life for as long as possible.