Been there done that. Article 15 UCMJ, challenged it to a Courts Martial, all charges dropped. 1983 on a false positive on a drug screening. Second and subsequent tests came up negative, the command still decided to mast me. So I requested a courts martial. After 6 months, charges dropped, qualifications reinstated. Vindication.
Operation "golden flow" (random drug urinalysis) was a hot topic when I was an active duty USAF Jag. A fellow Jag I knew and tried a couple cases with during service (Capt Lindsey Graham, now Senator (Col Res) from S. Carolina), challenged a whole series of cases of positive screenings in trials by courts martial. While assigned as an Area Defense Counsel, he pretty much single handedly challeged the USAF Brooks Laboratory (TX) which analyzed all the urine samples....and won. It was discovered that the civilian personnel at the lab were screwing up the "chain of custody" records, cooking tacos in the testing equipment, and otherwise doing shoddy work. He obtained numerous acquittals at trial, which resulted in good deal of embarrassment to the USAF, and a top-down revamping of how Brooks lab did business.
During this time, I came up for a random urinalysis, and though I knew I was clean, I was sufficiently worried about a false positive that I arranged to have two samples taken, and had my 2d sample documented on chain of custody to a secure location beyond my reach; so I had a backup if it came back positive. When it came back negative, I told my guy he could dump out my backup sample (from his safe, no refrigeration necessary). LOL
After Brooks Lab was revamped, however, their results were bulletproof, and remain so to my knowledge.
