Help I have a friend who is a gym goer Im not sure of his quantity or how long he has been taking steroids, but stopped recently because he had really bad neck pain. No dr or scan, ultrasound etc showed anything. Put on huge pain killer amounts didnt help alot but felt after about six weeks some relief. Until today when he thinks a prior knee issue has flared up. If this a result of steroid abuse how long before it heals? Im pretty sure he wont touch them again. He can handle all over aches and pains but these last two injuries have had him off work.
There are five primary color-tests reagents used for general screening purposes. The Marquis reagent turns into a variety of colors when in the presence of different substances. Dille-Koppanyi reagent uses two chemical solutions which turns a violet-blue color in the presence of barbiturates. Duquenois-Levine reagent is a series of chemical solutions that turn to the color of purple when the vegetation of marijuana is added. Van Urk reagent turns blue-purple when in the presence of LSD. Scott Test's chemical solution shows up as a faint blue for cocaine base. 
In the US, the most common form of steroid testing is more sophisticated than any of these three. It’s called antibody-antigen based radioimmunoassay. This term may sound complicated, but simply put, it uses a series of antibodies to seek out and measure the concentrations of antigens in the body. Hormones like anabolic steroids are considered antigens for this purpose, and the test is surprisingly accurate. If an individual tests positive, though, chromatography is performed. This process passes either blood or urine through a very specific medium to measure the rates at which different components move. It is even more accurate than the radioimmunoassay procedure, and is used mostly by anti-doping agencies.