Why Cant I Eat Before I Have My Blood Drawn

Were you instructed by your doctor to refrain from eating in the hours before you need to have blood drawn?  When you have specific blood drawn to test for disease, illness, or any other health concerns that may flag the need to change your lifestyle or diet, you may need to fast in the hours leading up to the test.  Although our dermatology pathology lab service in Pittsburgh serves many medical facilities, we also strive to help patients understand the reasons for our testing services. Blood tests are some of the most common diagnostic tests that can indicate a range of illness or irregularities, like high blood sugar, cholesterol, or low mineral levels.  There are a few reasons why you may not be able to eat before you have your blood drawn for diagnostic purposes.

Tests for Blood Sugar Levels

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.

Tests for High Cholesterol Levels

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.

Tests for Low Iron Levels

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.

Tests for Electrolytes and Proper Kidney Function

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.

When you have your blood drawn for diagnostic testing, you will want to follow the recommendations of your doctor so that you don't taint the results.  If your results end up tainted, you could have the repeat the process over and over again until the doctor gets the data he needs.  Contact our quality dermatology pathology lab service in  Pittsburgh, PA to hear more about how we can help with your diagnostic testing needs today.