How do doctors determine a teen is suicidal if many teens think about it at some time?

By asking: There are excellenet screeners some doctors use, but the main point is to ask--which you can do too. Fortunately suicidal thoughts are much, much more common than actual suicides. Many web sites list risk factors. Briefly, depression, drug or alcohol use, and social isolation are among them; a *big*, acute risk is sudden loss or humiliation. No blood tests, and teens lie, so trust your gut.

If you have a though: thought/ and a specific plan and there are warning signs. Giving away possessions, isolating, crying, acting strange, stealing, running away, acting erratically and not caring for the consequences, saying extreme things, having pills/guns/knives/blades will cause a Dr to take your/a persons suicidal threats VERY SERIOUSLY. So yes it can be determined. I have done this on the ER and on psych wards