Glucometer giving erratic readings. will be 101 in one sample, then 81 in another, immediately after. calibrated correctly too. is this typical?

Variation: Hi. Yes, that would be considered probably acceptable variation. They would generally probably be tighter, but if your control solution gets measured in the appropriate range, then your meter is probably meeting performance standards. We endocrinologists all get meters to give to patients, so ask your endo for a new one if yours is old and you're concerned about its performance. Good control!