why do the ask you not to eat before they take a blood&urine sample?

[22simple]

I am doing this study and you have to have a medical checkup (blood test, urine sample) and they asked me not to eat 8hrs before i go in i want to know why that is?

[Robinia]

It's so that the amount of sugar & cholesterol in them can be measured accurately.
The figure would be affected by food.

[Bazzdude2112]

A fasting blood test is used to determine blood sugar and cholesterol readings and also shows up any problem with the liver.

As a diabetic I have one every six months

[Mr k]

I agree with Bazzdude
But on 2 occasions last year while having my cholesterol checked they told me i didn't have to fast.
Whether they were checking it a different way i don't no....
I will ask next time i get it checked.