Can they find THC in my blood if they are testing it for HIV?

I guess it would depend. Often, the first round test for HIV involves a finger prick, and that is testing for HIV only. It won't tell you anything whatsoever about what is in your blood-- no other diseases, no drugs, period. If someone is checking for HIV during a blood draw, they aren't checking for drugs. read more

They're not sitting with your blood under a microscope looking for HIV and going, “My word, this person has smoking marijuana!” But they do have your blood, so they could order an additional test, I suppose: the doctor could theoretically order a drug screen along with the HIV screen. read more

Urine testing looks for the presence of THC metabolites rather than THC itself. While a blood test can detect cannabis use for a maximum of about 7 days after consuming, your urine may test positive for THC for as long as 100 days. It really depends on how much you consume and how often. read more

Here's how it works: You smoke marijuana. I take a sample (usually urine, sometimes blood) from you. I use an assay that will try and grab the chemical THC out of your sample. If you smoked marijuana, I'll find THC in your sample. If you haven't smoked it (at least not recently) I won't find it. read more