Eating before lactose intolerance blood test? I'm just curious how that would affect the results. there's a general rule that you shouldn't eat 8-10 hours before the test but if you were to eat during that time would the results then show that you're lactose intolerant if you really aren't or vice versa?
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replied March 25th, 2012
Welcome to e health forum.

Lactose tolerance tests measure the ability of your intestines to break down lactose, a type of sugar found in milk and other dairy products.

The lactose tolerance blood test looks for glucose in your blood. Your body creates glucose when lactose breaks down.
For this test, after an overnight fast (8 hours), you drink the lactose solution (usually 0.75 to 1.5 gm of lactose per kg of body weight), and serial blood samples are drawn and analyzed for glucose. If the level of blood glucose rises more than 25 mg/100ml, it means that the lactose has been split in the intestine and the resulting glucose has been absorbed into the blood. This implies that lactase levels are normal.

In case, you have not maintained a normal fast for 8 hours before the test, then the results may be not reliable, and the test might need to be repeated, especially, if the results are indeterminate.

I hope this helps.

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