My son had a drug test, but my question is has anyone had a doctor's office call you about it, and if so why would they do that?

They might not call you if he's over 18. If he's under 18 they will probably call and disclose information to you

1 let you know the results of the test.

2. let you know if they noticed some other problem ( not sure what, but you never know

3. call and ask about payment for the test

4 call because he did not come back in for results as requested?

I could keep coming up with reasons, but unless you ask him or the doctor, you won't know