Do I understand correctly that you will be using an insulin needle for kitty's ear test poke? I wouldn't recommend doing that. For home testing, I'd suggest using lancets to get a blood sample from kitty's outer ear. The larger the gauge number, the thinner the lancing needle. I use 33 gauge lancets when Hannah's ears are already warm and will likely bleed productively. When her ears feel cold to the touch, I first warm them with a pill bottle filled with warm water (cap on, of course), then use a 30 gauge lancet. I do not poke freehand, as the lancing device works well for me and Hannah doesn't mind the click. However, you can still poke freehand, using just the lancets without the lancing device. The lancets are very inexpensive, insulin needles... not so much. Hope this helps and best of luck.
Lancets for alternate site testing are most successful getting a blood drop when first testing. These are 25-28 gauge and thicker than insulin syringes.
I see why the lancet is a better option now than the syringe needle the vet used. Less chance of the needle going right through the ear. Puts my mind at ease.The syringe needle is definitely longer. The lancet has a maybe 1/8 inch pin.
You can use a rice sock heated in the microwave, as well as gently massaging the ear. Whatever you use should not add moisture to the ear, as it will affect the concentration of the blood sample and give an inaccurate reading. When I was very new to ear testing, I used nothing except a gentle rubbing of the area to be tested. It was in the summer and the weather was quite warm, so Hannah's ears only needed a little encouragement to provide a sample. In the winter and colder months, however, massaging didn't work very well, so I recruited the help of a pill bottle filled with warm water. Also, to keep the lancet from pricking your finger on the underside of kitty's ear, you can use a cotton ball, folded up tissue, or a gauze pad to support the prick and avoid testing yourself. Ouch! I learned that by experience.Would a warm compress or massaging the ear work as well?
The outer edges of the ears have the fewest pain receptors...that's why most cats don't mind the testing (It really doesn't hurt)
As you poke more and more, the ears will grow new capillaries in the area you're poking. We call it "learning to bleed". Within a week or two, one poke will probably provide more than enough blood for testing.
In the meantime, make sure the ear is warm before you poke it, and if you're going to use 30 gauge lancets, you may have to poke twice really close together. It may be easier if you get the "alternate site testing" lancets that are 26-28 gauge since they make a bigger "hole"