Blood Sugar Monitoring

Home Monitoring * Continuous Monitoring * Some Quick Info

Key Points

  • If you are going to be doing a curve, or if your cat is particularly resistant to ear sticks, ask your vet about topical ear numbing medications to keep kitty more comfortable. I saw this option mentioned in the Idea Exchange for DVM360
  • A very light coat of Vaseline on the ear can help the blood to form a bead rather than spreading out on the ear, making collection easier
  • When pricking the ear you will likely want to have a cotton pad or cotton ball in between the ear and your finger on the the other side. In the event you stick through the ear the cotton ball will protect you from getting stuck with the same needle
  • Warming the ears up before collecting the sample will help you to more easily locate the small vein you need to poke, and will ensure you get enough blood from a single stick.
    • You can warm the ears by rubbing them, or by holding a warm pack in place
    • You can make a DIY warming pack with a small sock pouch filled with uncooked rice and microwaved for about 45 seconds. The pack should feel comfortably warm if you put it to your own ear, never hot. If the pack is too hot simply let it cool down a bit before you use it.

Home Monitoring

Blood sugar monitoring in a diabetic cat is very important. Home monitoring allows you safely administer insulin only when necessary and is the best way to avoid over medicating your cat.

Giving insulin when blood sugar levels are normal can be fatal. Testing the blood sugar before every single dose can save your cat’s life.

This video explains how to use a home glucose monitor.

This is probably my favorite video on how to test your cat’s blood sugar levels.

This next video has a very simple instruction on how to test the blood sugar in a cat. There are a couple points I want to make before you watch it.

  • The cat in this video is very docile. That does not always happen at home. Do not be surprised if your cat reacts differently.
  • If your cat takes a little while to calm down prior to collecting the sample, you may want to prepare your glucometer by putting the test strip in it, but not pressing it all the way in. Once the strip is all the way in you have a limited amount of time to collect a sample. If you have the strip ready to lock into place you can take as long as you need to calm your cat. Then, when ready, push the strip the rest of the way into the machine just before sticking the ear.
  • The blood sugar level demonstrated in this video is given in international units. If you are in the United States you will be using different units, so your result will be different.

Glucose Curves

A glucose curve is a series of blood glucose measurements made after a dose of insulin is given. Typically, blood samples are taken every 1 1/2 to 2 hours until the effects of the insulin injection can be determined. For ease of understanding, they are often plotted on a graph.

Periodically performing a glucose curve is also important in understanding how your cat is responding to their insulin therapy. You can do a full curve or a mini-curve. If you are unable to do the curve yourself, you can also talk to your veterinarian and schedule a drop-off day for your cat where the staff will perform the required testing for you.

Continuous Monitoring

Continuous monitoring of glucose levels is also possible using the Freestyle Libre monitor. This is the only implantable monitor currently that does not require taking additional samples during the day to calibrate the device. And it can be worn for up to 14 days before being replaced. The other available monitors on the market all require replacement after about 7 days.

How quick and easy is it to check glucose levels using Freestyle Libre? Let me show you!

One important distinction is that Freestyle Libre is monitoring interstitial glucose levels (glucose between the cells) and not blood glucose levels. The glucose measured using a blood sample will be different from the interstitial glucose readings. In my own cats the blood glucose levels are typically 72-75 mg/dL higher than the interstitial glucose levels. It is a good idea to test your cat’s blood glucose a few times while they’re wearing a Freestyle Libre sensor so that you can get a feel for how your cat’s readings might differ.

My own diabetic cats are using the Freestyle Libre sensors now. You can read about our progress with them here.

If you’re in the United States and looking into getting the Freestyle Libre monitor for your cat be sure to look at my tips for saving money on human prescriptions to get information on how to use GoodRx and other pharmacy discount cards and clubs to save on the purchase price.

Here’s a really informative video explaining both the sensor, and how to apply it.

This is a fairly short video showing a vet applying the sensor to a dog. I couldn’t find any short videos showing application on a cat.

Sensor Placement

I’ve seen some photos of cats wearing the sensor on their necks and using the Kitty Kollar as a cover.

Muffy had her sensor placed on her shoulder. I didn’t put any kind of cover over hers, because she didn’t care about the sensor at all.

Some Quick Info

  • In Arizona, using Walgreens pharmacy, and receiving a discount that the pharmacist found (I don’t know which discount, but it was NOT GoodRx) I paid:
    • $64.99 for the reader device (July 2019). This is a one-time purchase.
    • $74.96 for a 2-pack of sensors (July 2019). Each sensor is good for up to 14 days, but can only be applied once. If it falls off before 14 days then it can’t be used again.
  • Certain smart phones can be used in place of the reader device using the FreeStyle LibreLink app. You can check compatibility at (you will need to click your language preference at that link before being taken to the list.).
    • My internal medicine vet has said that it’s easier for her to get results directly from the reader than it is from the app
  • The reader device is linked to a single sensor for the life of the sensor.
    • If you have 2 cats using this system you will need 2 readers (or one reader and one compatible smart phone)
    • I don’t know if you would need 2 different versions of the app if you use that in place of the reader
  • The sensors test for interstitial glucose levels every 15 minutes and store 8 hours worth of readings at a time
    • You can force test glucose as often as every minute using an option in the reader device that allows you to “check now”
  • Scanning the sensor with the reader device or smartphone will upload all the glucose measurements stored in the sensor that have not already been uploaded to your reader device
  • The reader device has a built-in FreeStyle Precision Neo blood glucose meter. You can manually check blood sugar readings using the appropriate strips through the same machine
  • The sensor is accurate for readings from 40 to 500 mg/dL
    • If the sensor takes a reading that exceeds that range in either direction you will be prompted to manually check blood sugar levels