If you're still talking about the MCAT in this case, then you should be worried sick. Many brilliant doctors would score below 25, due to the test materials not having to do much about medicine except 1 section (Bio sci). No matter how good doctors they are, they cannot remember those stupid physic equations, and don't care much about those damn humanity, political, philosophical passages.
SO to the OP, I think the only helpful test to know if you're gonna be successful in medical school is your score on the bio sci section. All the fundamental concepts, logic and explanations, they're all there. If you got a high score on that section (12-15), then you're golden.