Why can’t you eat past a certain time at night if you have to take a blood test the next morning?

Question

I am supposed to take a blood test in the morning and my doctor told me that I have to do it on an empty stomach, and can’t eat anything after 9pm. I understand how alcohol, for one, could impact blood test results but why food? Asking cause I’m hungry 🙁

In: Biology

Answer 1

Depends on the tests done but most commonly fasting is required when testing for blood sugar levels. The reason is, depending upon when you eat, what you eat and how much you eat, your blood sugar can vary drastically. So it is difficult to make an interpretation of the blood glucose levels in so many varying situations. Scientists found that a fasting period of 8 to 12 hours allows any excess sugar in the blood to be metabolised and gives a more standardised, comparable picture of the glucose levels.