Reader Question: Is a blood sugar or cholesterol test accurate if you haven't fasted prior to taking it?
Generally speaking, it's better to fast before these kinds of tests. If you're being screened for diabetes, a fasting blood sugar test—before which you shouldn't eat anything for at least nine hours—is most accurate. (If you take this test without fasting, be sure to let your doctor know so that he or she can correctly evaluate your results.) For a total cholesterol check, you may not need to fast; however, if you want a breakdown of your blood lipids (HDL, LDL and triglycerides), it is necessary to abstain from food for a period of time.
The best thing to do if you need blood work is to make your appointment for first thing in the morning. That way, you can simply skip breakfast when you wake up, and bring a snack along to the doctor's office to eat right after the tests are completed. And remember, while you can't eat anything before a fasting test, you can drink water—and you should. Drinking water will plump up your blood vessels and make it easier for the technician to draw your blood.
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