Blood test/Full medical checkup (for a unusual job).. do they tryout for drugs or a short time ago for serious illneses/disease?

I am curious on this. Do these medical checkups also include test on drug usage or intake.
*Curiosity kill the cat*Blood test/Full medical checkup (for a unusual job).. do they tryout for drugs or a short time ago for serious illneses/disease?
The employer often get a full set of tests since they are roughly the same cost as a more constrained series.
I know someone who had a liver enzyme abnormality (not a disease in recent times a freaky set of triglyceride levels). The company withdrew its opportunity offer until he proved he be not an alcoholic whose liver enzymes were ruined by cirrhosis of the liver.
It's entirely up to company policy. Comprehensive drug screen can be pretty pricey, so not every company wants to wage for them.