Blood Drug Testing

When having a fasting lab blood test, why do they tell you to avoid fatty and greasy foods in your last meal?

The directions say to avoid fatty, creamy, oily, fried, gravy, or whole milk & that kind of food during the final meal, 12 hours before the blood test. I understand why you need to fast after that, but what's the reason for not eating fatty foods pre-fast?

Public Comments

1. so that nothing isnt in your body except your blood so they can get all the right information..probably if you eat a whole bunch of crap an d whhen they do the blood test it might say other wise than whats really in your blood...and next thing you know you might be taking medicine for something you dont have but you wont know until something bad really happens (God Forbid) I guess thats why..
2. The people who have done the test probably have found that if you eat those things 12 hours before the test then it will skew the results. So, they can tell you to simply fast for 12 hours and don't eat those things. It is most likely that or fasting for more than 12 hours. Which would you prefer?
3. They are testing you for cholesterol, and fatty foods could temporarily increase your cholesterol, giving an invalid reading. It's not sure that they would be completely out of your blood in 12 hrs.
4. when you sleep your body makes cholesterol, so the food you've eaten in the last meal is what the body makes it out of. If it's high in fat and cholesterol it may cause your test to be artificially high. In reality it would be a gould idea to always make sure the last meal of the day fits thoses directions.