One of my friends, who corrected my manuscript, said this sentence wasn't immediately obvious to her.
The sample was screened for birth defects and major disabilities.
It's supposed to mean that the final sample/result of screening process didn't contain any people with birth defects and major disabilities, because we checked for it and rejected anybody who had such disabilities (to preclude alternative explanations for our findings).
Now I find that the word is less clear than I thought based on what I read in scientific papers (can mean both selecting AND rejecting).
I'm not sure if "screened for" is already clear enough (from the article context it should be obvious that we weren't interested in birth defects) or if I can use another preposition to be able to keep this simple sentence and still let everybody know that the final sample didn't contain any people with birth defects etc.