If you have a diabetic cat and are trying to monitor the glucose, ask your vet to demonstrate the PROPER way to obtain a blood sample. Some may prefer you use urine strips though for at-home monitoring.

As mentioned, glucometers are typically calibrated per species. The ones we use at work we have to calibrate not only between species, but per batch of strips we get (the "code" for the species may change with every vial of strips we get). I'm sure you can use your human glucometer to monitor your cat's blood glucose but you will need to talk with your vet about calibrating, etc.

If your cat has NOT been diagnosed, but you are concerned that your cat is diabetic, a blood glucose is NOT the only test necessary to diagnose this. Again, please speak with your vet if you're concerned your cat is diabetic, as other diagnostic tests besides a blood glucose curve are necessary.