When your body stores too much iron, your liver may be affected and release certain enzymes into your bloodstream. Your health-care provider may wish to test your blood for any or all of several liver enzymes or for various indicators of your iron levels. This blood work may reveal a need for further tests, some of which may require advance preparation by the donor. Fasting for several hours or overnight is commonly requested to ensure that your blood sample reflects your normal blood chemistry.
Reasons to Test Liver Enzymes
Iron-deficiency anemia, a condition of low blood count due to low iron levels, and hemochromatosis, a condition of iron overload, both signal that the body is abnormally processing dietary iron. Underlying causes may be related to diet, blood loss, medication interaction or physical malfunction. Your doctor can use blood tests to assist in diagnosing the source of unusual iron or liver enzyme blood levels.
Your Blood Test
Depending on your health condition, the blood sample that you will provide may be tested specifically for liver function in a group of tests called a liver panel. Your health-care provider may also wish to evaluate other factors in your blood and organs and request a battery of tests that includes liver function assessment and blood glucose analysis in a comprehensive metabolic panel. You may be asked to give a single blood specimen or to provide one after fasting and one without fasting. Your doctor will let you know which process you will undergo.
You may be asked to fast for 10 to 12 hours before giving blood for testing. The typical fast restricts your diet to water only during that time. If, among your combined tests, some do and some don't require fasting, you will need to fast so that the overall outcome will be accurate. Because rules may differ among testing laboratories, follow the guidelines provided by your doctor or the lab itself, or request help if you need it.
Your Blood Sample
Your adherence to fasting will determine how quick and precise the assessment of your blood specimen will be. If you eat or drink any substances other than water beforehand, you may have to reschedule the test and start over. To deliver the best possible blood sample, be sure to avoid consuming solid foods, juice, coffee, tea, soda, alcohol, candy, gum or any other foods or beverages.