My son repeatidly test positive for thc metabolites in urinalysis test,but has not used marijuana in months ,will a hair folical test prove this is past residue and not recent use?

THC-COOH is the long lasting metabolite of THC that eventually winds up in the urine. There are several conditions that have been tied to the residual appearance of COOH in urine. 1) Weight loss, 2) exercise (because muscle displaces fat). Both are related to the fact that THC and 11-OH-THC bind to fatty tissue. Another cause is stress.

Hair analysis may or may not be helpful. It is hit and miss with THC.