How are urine drug tests and hair follicle tests related?

Question

Hello doctor,

I am trying to figure out the conversation between levels on a urine drug test and a hair follicle test. For example, urine test: 505 ng/ml. THCA. Hair test: 5.95 pg/mg THCA. If there were 32.6 ng/ml of cocaine metabolite detected in a urine test, how might that show in a hair drug test? There seems to be a correlation between the THCA levels, but I cannot figure out what the connection might be.

Kindly help.

Answer 1

Hello,

Welcome to icliniq.com.

In the urine, the metabolites are detected as it is directly coming out from the blood. I mean, it gives a day-to-day excretion of the metabolite that is directly proportional to the amount of the specific drug or metabolite in the blood. Whereas, the metabolites or drugs in the hair tell the history of any drug or chemical usage.

As we know, the growth of hair is very minimal daily. Certain chemicals or drugs or metabolites can get accumulated in the hair on a long-term basis. So, if we could find the THCA (tetrahydrocannabinolic acid) in hair, it would be telling the past blood concentration or usage of the THCA. Thus, the hair value may not usually be proportional to urine values.

I hope I have answered.