Doing Ear Pricks to Test Your Diabetic Cat
Home glucose monitoring is easily accomplished by using a glucometer and pricking a vein or capillary in your cat's ear or foot. Materials needed, the method, and some reader tips are found in the section Home Blood Glucose Testing of the Diabetic Cat.
One feline caretaker, Donna B., wrote the following description of ear pricks.
Contributed by Donna B.
I am not a veterinarian. I am the caregiver for a diabetic cat. These ideas and descriptions are not intended to be substituted for proper veterinary care. They are from my personal experience with my diabetic cat and are intended to provide ideas and helpful hints about home blood glucose monitoring and the ear prick method.
Managing diabetes is very complicated. Blood glucose (BG) readings can change depending on food consumption, exercise, stress, and normal daily fluctuations. There may also be other diseases or conditions that are effecting the cats health. Home blood glucose monitoring should be performed in consultation with your veterinarian.
I take my cat to a veterinarian who knows I am able to perform home monitoring and who is supportive of home testing. I recommend home BG monitoring to anyone who feels comfortable performing the tests, has a cooperative cat, and has a veterinarian who will work with them.
PURPOSE OF HOME BLOOD GLUCOSE MONITORING
Home BG monitoring is a useful tool to help you and your veterinarian get your cats diabetes regulated. It can be used to determine how well the current type and dose of insulin is controlling the diabetes. This determination is best done under typical daily conditions. The cats feeding, exercise, and stress levels should be near normal. One common problem with doing BG testing in the vets office is that many cats become severely stressed, refuse to eat, are confined to a cage for a long period of time, then restrained for a blood test. These are not normal conditions and the BG values obtained at the vets office may not accurately reflect what the BG is doing on a typical day.
If your cats diabetes is pretty well regulated, home BG monitoring can be used to check your cats BG on an occasional basis or to fine tune the control. You can perform a BG test at any time, quickly and conveniently.
Many different home blood glucose meters are available. I use the Glucometer Elite by Bayer. It requires a very small blood sample and is very easy to use. There are some general tips for the Glucometer Elite at the end of the ear prick description. Always be sure to read, understand, and follow the instructions provided with your meter and the test strips.
VERY BASIC ANATOMY FOR THE EAR PRICK METHOD
There is a small blood vessel that runs around the outer edge of the cats ear about 2-3 mm from the edge of the ear. To locate the blood vessel hold a flashlight (or sit near a bright lamp) with the light shining into the inside of the ear. Look on the back (furry side) of the ear. You should see the a thin red line - this is the blood vessel.
Keep everything very clean. Thoroughly wash your hands with soap and water. Have a clean work surface or put out a clean towel to lay things on. Do not touch the tip of the lancet.
The ear must be perfectly dry and very clean before you prick it. If the surface of the ear is dirty wash the ear with warm water. You must wait until the ear is completely dry before you can perform the ear prick. Moisture will cause the blood drop to spread out and it will be difficult to perform the BG test. Moisture will also dilute the blood sample and cause a faulty BG reading.
Gently restrain the cat. This procedure requires keeping the cat calm and still for a few minutes. The cat must be relatively relaxed. If you cause a lot of stress to the cat while trying to restrain it you may not get an accurate BG reading. Of course there may be a little struggling, but if the cat becomes highly agitated, I would wait 15-30 minutes and try again. Ask your veterinarian to show you how to properly restrain you cat. NEVER use excessive force.
Controlling bleeding. After I get the blood sample in the meter, I let the meter do its work and attend to the cats ear. I hold a gauze square firmly (not too tight) around the ear where I pricked it. I hold it for about 30 seconds. This has been enough time for the bleeding to stop. I have never had a problem with excessive bleeding.
If the ear continues to bleed, keep applying gentle pressure for another minute. Dont "peek" to see if the bleeding has stopped. Just firmly hold the ear and keep the cat calm. If the bleeding does not stop or if a large bruise forms call your veterinarian for advice.
Bruising. a small red spot may form after the prick. This is where a small amount of blood has leaked from the blood vessel and is trapped beneath the skin. A small bruise is ok (the size of a grain of rice). The bruises on our cat go away in about 2 days.
Watch for any large bruising (larger than a grain of rice). Also watch for any signs of swelling, fluid accumulation, warmth in the area, or infection. If you think any of these are happening call your veterinarian for advice.
What the numbers mean. The BG value tells how much glucose is in the cats blood. My meter reports the units in mg/dL - that is milligrams of glucose per deciliter of blood. Normal values are around 80-120. I do not want to give advice on what to do when you get a specific BG value. That is for you and your veterinarian to discuss. Your vet should have told you what the signs of hypoglycemia are and what to do to treat it. I will say that our cat has had a few low BG readings. Once his BG near 40 mg/dL. We immediately fed him and watched him very closely for any signs of hypoglycemia. Be aware that you cat can have very low BG and not show any outward signs of hypoglycemia. Again, it is very important that you have discussed hypoglycemia and the immediate treatment with your vet.
HOW I DO AN EAR PRICK:
I wash my hands and prepare all the supplies: clean work area, BG meter, test strip, gauze, lancet, and cat. I purchased a package of 1 inch by 1 inch gauze squares from the drug store. Some people use cotton balls. If you use cotton balls, I recommend the 100% cotton balls, not the synthetic type. I use the Glucometer Elite meter and its test strips, and B-D Ultrafine lancets.
For our cat, it works best if he is sleeping or very relaxed. If he is at all agitated or in an active mood we usually can not hold him still without him getting very upset. He does not like to be even lightly restrained. Usually we let him lay on a chair, pet his head and neck and just hold his head and ear still.
I make sure the ear is very warm. It is difficult to get a drop of blood from a cold ear. Petting or massaging the ear usually gets it warm enough for the blood to be flowing well. If the ear is really cold you may need to massage for 5 minutes. I have even used a small warm water bottle (a warm washcloth folded up inside a plastic zip-lock bag). I hold the warm bag against the ear I am going to prick. The wash cloth is not too hot; I am be able to comfortably hold the wash cloth in my bare hand.
When the ears are warm to the touch I can easily see the blood vessel at the edge of the ear.
The cat is facing away from me. It doesnt matter if he is laying on the floor, in a chair, or on my lap. I just get behind him or a bit to the side so that I am comfortable and the light from a lamp is shining through his ear and I can see the vessel.
I prick from the back side of the ear towards the inside. My pricking hand (right hand) is behind the cats head and ear. With my left hand I hold a folded gauze pad on the inside of his ear. With my thumb and first two fingers I hold the gauze against his ear....my thumb is on the back of his ear and my other two fingers hold the gauze firmly against the inside of his ear. I can hold the ear steady and I have something firm (the gauze) to prick against. I roll his ear a little to the inside (towards my first two fingers) so it is a firm area to prick against. I want the ear to stay tight against my fingers so the lancet goes into the ear instead of pushing the ear away.
I position my left hand so that I can prick the ear just below my thumb.
I prick the ear about 2/3 the way up the ear, or about 1/3 from the tip of the ear. If I go too far towards the base of the ear, it seems to cause more discomfort. If I prick too near the tip of the ear, I dont get a big enough drop of blood.
Usually, I prick all the way through his ear. Pricking all the way through the ear does not seem to hurt him any more than a shallow prick.
I prick the ear using the lancet by hand, I don't use the automatic device. I have much better control of the lancet and can aim directly for the blood vessel.
I try to do one, firm, quick prick. I try to hit the blood vessel directly so that a large enough blood drop forms quickly. If I miss the vessel not enough blood comes out. If the blood drop does not form immediately I gently massage from the base of the ear towards where the prick is. This may help a blood drop form. I dont squeeze too hard or too long. I try not to "milk" or squeeze blood from the ear. It usually causes a larger bruise. If a drop of blood does not form in about 15 seconds, I try another prick.
Sometimes the drop of blood forms on the inside of the ear. Thats ok. You can use that drop.
As the drop of blood forms, I try to keep hold of the ear so the cat cant flick the drop away. When I think the drop is big enough I put the meter, which has the test strip in it, up to the blood. The test strip automatically "pulls" the drop of blood into the test chamber.
You must follow the instructions for your meter. The amount of blood needed depends on the BG meter. After a few tries, you will be able to tell when you have a big enough drop of blood.
I record the date, time, and BG value.
BG TESTING THINGS TO REMEMBER
I follow the instructions that come with my meter and the test strips. Failure to follow the instructions may result in a faulty BG reading. Make sure your meter is calibrated according to the instructions.
I try to repeat the BG test if a result seems faulty.
I DO NOT base any decisions on just a few tests.
I consult with my veterinarian. I tell him the BG values and ask his advice.
This is how I do BG tests on my cat. They are ideas for you to use or modify. You will have to try different things that work for you and your cat. You may have to modify the methods if you are doing the testing alone or if another person is helping.
TIPS FOR THE GLUCOMETER ELITE
I partially insert the test strip before the pick, then fully insert it (you hear a beep) after I have warmed the cats ears and just before I am ready to do the actual prick. The meter beeps when the test strip is correctly inserted. After the beep, the meter allows 3 minutes to get a drop of blood. The 3 minute time is a battery saving function of the meter. The test strip is still good after 3 minutes.
If you cant get a drop of blood in 3 minutes, remove the test strip (I use a piece of gauze to grab hold of the strip), wait a few seconds, then re-insert the strip. This will give you another 3 minutes.
You must get the required amount of blood into the test strip all at once. The meter beeps when it has enough blood. If you try to get blood into the meter and the meter doesnt beep, you can NOT do another prick, then get more blood into the strip until it beeps. The BG value may be invalid. If you dont get enough blood on the first try, discard the test strip, use a new test strip, and try again