Can a toxic liver be detected from a blood test?

A standard blood test will tell whether your liver is functioning properly. If there is a problem then you will need a more specific test to determine the cause.

There's no such thing as a "standard blood test". There are a couple of common blood tests but there is no generic blood test.

Liver function tests, which are commonly ordered, will obviously show liver damage.

The so-called standard blood test should be regarded as a screening test to separate the normal population from those more likely to have certain problems. An abnormal screening test suggests that the physician should order more specific diagnostic tests.

So the answer is yes, maybe.

It sounds like you're asking if a blood test will reveal liver damage caused by drug abuse, and your parents will find out. All I can say is that I hope so.