Answer: Many factors come into play, like how tall he is in relation to the 190lbs. THC is stored in the adipose tissue, so the more you have the more likely it is kept there. Also individuals metabolize substances at different rates. However, 21 days for a reasonably fit person is probably adequate time for marijuana traces from a single joint to leave the system as far as urinalysis goes (more invasive testing is another story). Remembering to be hydrated will also dilute any minor concentrations within the urine making it even less likely to be found. Good luck smokey...
Answer: If you show signs of steroid use, either physically or behaviorally, they can and will. Especially if you are on PRP[Personal Reliability Program].All branches of the Military do random drug testing. but if your immediate superior or Primary Care Manager suspects steroid use they can order you tested and you must comply.
Answer: Depends on whether or not it shows possible infection or something. If positive for infection then culture would be needed. Another cost. Call a lab in your area for cash pays they do charge less.
Answer: yes. Most urinalysis will be comparing to a given chart, the person reading compares the colour to that on a chart given on the container. None of the tests rely on being able to interpret green vs blue as far as i am aware.