If its his lipid panel (Cholesterol, triglycerides, LDL ratio etc.) that are out of range there isn't much he can do short term. Diet and AAS use will need to be looked at as well as certain lifestyle changes... these take time.
On the other hand, AST (SGOT) and ALT (SGPT)values ( transaminase enzymes ) which may indicate liver or kidney dysfunction or disease can possibly be lowered rather quickly by ceasing exercise for awhile precedeing the collection of the blood sample used in the test.
And like Div. said, more info would help