Testing Blood Glucose
Glucose can be measured in interstitial fluid or blood. Glucose in interstitial fluid is similar to blood glucose and can be measured using a continuous glucose monitor (a small monitor implanted under the skin for up to 2 weeks).
Glucose can also be measured in blood using a handheld glucometer or test strips, which only need a drop of blood, several times a day.
How to Collect a Blood Sample
There are a few options. Your veterinarian may collect a blood sample from a vein. The glucose concentrations are then measured in the laboratory. Only a drop of blood is needed if you are using a blood glucose test strip or a handheld glucometer to measure blood glucose. Your veterinarian will show you the most suitable place and method to collect a drop of blood from your dog’s ear (pinna), inner lip or elbow callus. Alternate sites, including tail and foot pads could be considered depending on you and your veterinarian’s preference and your dog’s comfort level.
Make sure that your dog’s ear is warm. If not, hold it between your hands for about 1 minute. This makes collecting a drop of blood easier.
Quickly prick a clean, hairless part of the ear with a sterile lancet or hypodermic needle.
Collect the small drop of blood that appears onto the glucose test strip as per the instructions provided.
Gently but firmly press some clean cotton or gauze onto your pet’s ear until bleeding stops.
Read the test strip or insert the sample into the glucometer as instructed.
Your veterinarian may want to make a blood glucose curve for your diabetic dog. When creating a glucose curve, remember that general health, feeding, exercise, insulin dose, and stress can affect the results and the glucose curve is only one tool among others that can help manage dogs with diabetes. As stress plays a role in glucose and insulin metabolism, your veterinarian might request that you collect blood samples from your dog at home over a certain period.
What is a glucose curve used for?
A blood glucose curve can help determine
- If and when the insulin given to your dog starts working
- How responsive your dog is to the insulin dose it has been given
- How low your dog’s blood glucose falls and when this occurs
- How long the insulin works in your dog
This information is used to monitor the response to an insulin dose – especially at the start of treatment or after a change in insulin dose. It is also used to investigate dogs that appear not to be responding to insulin treatment – sometimes after a period of stability.
When to take blood samples
- Just prior to giving insulin and food
- Then, every 60 to 120 minutes (with the shorter intervals particularly useful when blood glucose falls to 9 mmol/l or 162 mg/dl or lower)
- For as long as possible e.g. for 8 to 12 hours or longer
Your veterinarian will interpret the glucose curve based on your dog’s progress (e.g. water intake, appetite, attitude, body weight).