Kidney Disease Part 2, Diagnosis

Kidney disease is most often diagnosed by blood and urine testing. We will perform these tests if your pet isn’t well (increased thirst, weight loss, muscle weakness, vomiting or anorexia), but we also perform these tests as part of our senior wellness testing or pre-anesthesia testing prior to a surgical or dental procedure (most often in these cases your pet hasn’t been showing any clinical symptoms).

The challenge with traditional blood and urine testing is that they don’t tell us how much kidney function has been affected. In most pets, numbers don’t start to go above average range until 75% of the kidney function has been lost. Blood tests in the normal range indicate that the kidneys are currently able to do their job, but we don’t know if they have already lost some ability to function.

To assess kidney function, the primary tests we perform are urinalysis, BUN and Creatinine blood testing, electrolyte testing, phosphorus testing and looking for anemia and the newer SDMA (symmetric dimethylarginine test). These tests are all valuable, but some have advantages over others.

A urinalysis is performed to look at urine specific gravity and to make sure that the kidneys aren’t leaking proteins. Urine specific gravity can be affected by other causes of increased thirst, and a pet may have a low specific gravity and usually have functioning kidneys. Urine protein can be falsely elevated if the pet has a bladder infection or other inflammation and it isn’t specific to the kidney.

BUN (blood urea nitrogen) and creatinine are blood tests that are often performed together, BUN is created when the liver breaks down proteins, creatinine is a product of normal muscle breakdown, these waste products are typically eliminated from the body and lab testing showing high levels of BUN and Creatinine can indicate that the kidneys are not functioning correctly. The challenge with these blood tests is that they are a late marker and can be affected by other factors. BUN can be affected by many conditions including dehydration, bleeding in the digestive tract, liver disease and diet, creatinine can be affected by lean muscle mass, dehydration, hyperthyroidism and diet. Unfortunately sometimes when the testing is performed, and these values are elevated we are already dealing with a very sick animal who will also have an elevation in phosphorus, abnormal electrolytes and anemia.

SDMA is a newer test and it has been proven to be a more reliable indicator of kidney function than the previously mentioned tests. SDMA is considered a kidney-specific biomarker, it is excreted by the kidneys and reflects the filtering capacity of the kidney. SDMA will increase much earlier than creatinine (as early as a 25% decrease in function vs 75% for creatinine) and is impacted by less non-kidney factors.

Currently, we are sending SDMA testing to an external laboratory, but expect that it will soon be a routine part of most blood panels that we do in the clinic, this will hopefully help us pick up renal disease much earlier and extend the quality and lifetime of our pets who are affected by kidney disease.

In the next part of this series, we will discuss what we can do if there are elevations in SDMA or BUN and Creatinine. Early detection is essential and we are excited to have a new tool to help with this.

Written by by Jane Corkum, DVM


The Importance of Microchipping Your Pet

Pets can get lost which can be a traumatic and possibly tragic event.  It’s important to have a collar and ID tag, but these are not foolproof.  Collars can break or fall off leaving your pet unidentifiable. This can be prevented with the use of a microchip. As noted in the Dartmouth Tribune in April 2017: A pet is lost every seven seconds One in three pets will go missing in their lifetime Only 2 percent of lost cats and 17 percent of lost dogs with ID return home When a pet gets lost, they are 20 times more likely to make their way back home when they have a microchip A microchip is a small chip that is encoded with a unique identification number.  It is no bigger than a grain of rice and implanted just under the surface of your pet’s skin.  The process is similar to receiving a vaccination through a needle and is virtually painless to pets.  Once implanted, the microchip remains between the shoulder blades just beneath the skin for the rest of the animal’s lifetime, becoming a permanent form of identification. Since it’s under your pets’ skin it can’t break or fall off like a collar or tag. The chip is powered by a scanner which sends a signal to the chip and receives the identification number stored on it.  A vet or shelter can use the scanner to read your pet’s chip.  With the identification number, your pet’s information is a phone call away. When your pet is microchipped, it is linked to a database with your contact info.  It is essential that you register the microchip and ensure your contact information is kept up to date.  If you move or change phone numbers be sure to update your information.  Microchips are reliable and use nationwide registries, but they depend on the information you provide. If you want to improve your chances of getting your pet back home quickly and safely microchipping is highly recommended.   Written by Tracy LeFler, Site Coordinator Edited by Janis Wall, RVT

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Last updated: September 15, 2021

Dear Clients,

The health and safety of both you and our staff is our top priority. We appreciate your help in keeping our community safe by following our COVID-19 policies:

  • Masks are required for all clients entering our hospital, as well as for all our staff
  • 1 client per exam room allowed (exceptions will be made for end of life procedures)
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    Thank you for your patience and understanding and we look forward to seeing you and your furry family members again!

    - Your dedicated team at Westwood Hills Veterinary Hospital