Bandit fought me tooth and claw the first few weeks we tested! Here's what helped us:
1. My attitude. I started out being all "poor kitty! I hate to hurt you!", and this made things worse for both of us, because he could sense my lack of confidence. Once I changed my attitude to be, "You're getting this test, cat, whether you like it or not because you need it to save your life!", things went much more smoothly.
2. Blankets, and lots of them. I got a basket that was roughly the same size as Bandit on the suggestion of my vet, who said that ornery cats calm down when they are surrounded on all sides but the top. So Bandit went in the basket for each test, which I lined with fleece blankets, I had another fleece blanket I used to wrap him in so that only his head was free. This kept him from clawing me and trying to escape while I did the test.
3. Get the test as fast as you can. Use a thicker gauge lancet (26-28g), and make sure you're warming the ear to get the blood flowing. Back the ear with a a piece of tissue or a cotton pad so you get a firm poke, and put pressure on the poke spot for 20 seconds after the test to prevent bruising. A tiny bit of neosporin + pain relief in the beginning also helps.
4. End each test with a diabetic safe treat, no matter what it is. My cats like
these treats a lot. Any freeze dried, meat only treats will be diabetic safe.
If you establish this as a routine--basket, test, treat, then eventually the cat gets used the routine and accepts the testing. It took Bandit a few months, but now he comes running when he hears the meter beep on and sits patiently in front of me and purrs until his test is done. Keep in mind that testing does not hurt our cats--they have less nerve endings in their ears than people do in their fingers. They just don't like that you're doing something new and strange to them.