Crap! His A sample tested positive! I must be wrong about him being clean! I totally forgot about the low specificity of drug tests, but that makes no difference and those tests are 100& correct 100% of the time.
Its called a false positive. Clearly you don't think they happen. Maybe you should have your family member get a false positive for HIV for you to actually think they happen.
You can't pull it out because its too far up in there and much too large.