"The nurse told me I don't have to fast for my A1c test next week," she said.
This is Foil Hat Lady, one of our patients that's been a constant source of head-shaking for the pharmacy staff.
"Yes, that's correct," I said.
"But it's a blood sugar test. I always fasted before."
"This is different. It doesn't measure the amount of sugar in your blood stream. It measures the amount of sugar that's become stuck to your red blood cells over the past three months."
"I don't understand," she said. "I always fasted before. Are you sure I don't need to fast?" she asked.
I then tried to explain it to her the best I could. I told her how when you buy a new set of tires for your car... and how by the time you get home they're a little dirty with dust and dirt, but still look brand new. Then after time they get really dirty. I said our red blood cells are kind of like that. New red blood cells are only coated with a little bit of sugar whereas older ones have a lot more. By averaging that all out we can determine your A1c level and your diabetes status.
I thought it was a nice analogy since tires and red blood cells are round. I wanted to pat myself on the back.
"Well I'll fast anyway. I don't want to mess up the test," she said, then walked away.