One of my civies (non-diabetic cats) tests in the 40's. My sugardude Wink is usually somewhere in the 70-99 mg/dL range.
You know, Friskies is a good, inexpensive canned food. It may not have the highest quality of ingredients, but neither does the Hill's M/d or the Purina DM or the Royal Canin that the vet wants to sell you. The Friskies is what I feed my cats, along with some Fancy Feast. Not everyone can afford to feed the expensive prescription vet cat foods.
There are other foods that are appropriate for diabetic cats and this vet, Dr. Lisa Pierson, put together an
entire food chart with the protein, fat, carb and phosphorus content of the different canned foods. We suggest that anything with a carb % <10% is good for your diabetic cat.
You feed what you can afford. Plus, you are getting good results.
A curve or at least a couple of tests before food would give you a better idea if your cat Baby is in remission. Numbers can vary quite a bit during the day, so a single test is not an indicator that Baby is in remission. The clinical signs, like peeing, pooping, purring, preening, and playing tell you a lot too.
So, you might want to give home testing another try. Let us know how we can make this easier for you. We have lots of tips on testing, like warming the ear first.
Did your vet run a fructosamine test? That would be a better indicator of Baby's BG (blood glucose) levels over the past couple of weeks than a single test after she has been fed.