Reasons Why You Can't Eat before These Four Blood Tests

Have you been instructed to fast before getting your blood drawn?  Has your doctor told you that you cannot eat for at least 12 hours before you take a blood test?  When you are told not to eat, you likely immediately start to panic about being lightheaded, fainting, or just being uncomfortable.  As a dermatology pathology lab service in Dallas, TX, we understand the reasons behind why fasting is encouraged for certain tests.  We find that it becomes much easier to avoid eating foods when you know why you can't have them.   There are a few reasons why you can't eat before you have these blood tests done.

Blood Glucose Tests

Fasting glucose tests can determine and diagnose diabetes, which indicates that there is an issue with blood sugar levels in the body.   It is important for patients to avoid eating or drinking anything for 8 to 10 hours before having blood drawn to ensure that an accurate blood glucose level is being recorded.  This is essential in ruling out or diagnosing the possibility of diabetes.

Blood Cholesterol Tests

Having a high level of cholesterol can put you at risk for many other health conditions, which can have devastating effects on your health.  Blood cholesterol tests are used to indicate the levels of fats in the blood, which will naturally fluctuate once you have eaten certain foods.  Fasting for 9 to 12 hours before having blood drawn is important to give an accurate depiction of the levels of fats normally stored in your blood.

Iron Blood Tests

Blood that is drawn to test the levels of iron also require fasting.  These tests are done to determine whether you have a deficiency of iron in your blood, resulting in anemia.  Iron is absorbed very quickly from foods into the blood, so fasting for the morning before the test is essential in providing accurate results.  Also, those who take supplements should also refrain from taking those supplements for at least 24 hours before having their blood drawn.

Comprehensive Metabolic Tests

These tests are done in order to determine diseases or disorders related to the kidneys, blood sugar, and electrolyte balance.  When you have these tests completed, you will want to fast for at least 10-12 hours before having your blood drawn to provide accurate results that are tainted by eating particular foods first.

If you are having your blood drawn for one of these four blood tests, it is important to follow doctor's orders.  When you eat before you have these tests, you can taint the results, which will require retesting at our dermatology pathology lab service in Dallas, TX.  Our lab service provides diagnostic consultations, results, and data analysis to aide medical practices in patient care.  Contact us to hear about our lab testing capabilities today.