How you prepare
By Mayo Clinic staffIf your blood sample is being tested only for hemoglobin, you can eat and drink normally before the test. If your blood sample will be used for additional tests, you may need to fast for a certain amount of time before the test. Your doctor will give you specific instructions.
- Hemoglobin. In: Nicoll D, et al. Pocket Guide to Diagnostic Tests. 5th ed. New York, N.Y.: The McGraw-Hill Companies; 2008. http://www.accessmedicine.com/popup.aspx?aID=3136818&searchStr=hemoglobin. Accessed March 4, 2011.
- Hemoglobin. Lab Tests Online. http://labtestsonline.org/understanding/analytes/hemoglobin/glance.html. Accessed March 4, 2011.
- Laboratory reference values. Hematology group. Rochester, Minn.: Mayo Foundation for Medical Education and Research; February 2011.


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