DYESS AIR FORCE BASE, Texas -- A medical rocker mixes blood evenly to make sure that the anti-coagulant distributes evenly at the 7th Medical Group Lab, March 10. If blood sits for too long it will clot and it can not be tested. (U.S. Air Force photo by SrA Courtney Richardson)

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Photo by: SrA Courtney Richardson |  VIRIN: 080310-F-2300R-006.JPG