Airman 1st Class Reyna Lopez- Tegui, 779th Medical Group medical laboratory technician, holds a blood sample for a Complete Blood Count (CBC) test Jan. 31, 2013 at Joint Base Andrews, Md. The CBC test is used to evaluate one’s overall health and to detect a variety of disorders. (U.S. Air Force photo/ Airman 1st Class Erin O’Shea)