Jhill

That's why you do a dry and wet compression test. If an engine has sat or fuel has washed the rings out etc as squirt of oil through the spark plug holes and a retest will give a more realistic result.

Personally although it takes longer a leak down test will give a more accurate representation of an engines condition and how it will run. I've personally seen at least 3 engines that will pass a compression test yet have a misfire at idle due to valve leakage. Off idle the pistons move fast enough to not have a mis and will still build enough to pass a compression test but at idle it will still have a mis.