Facts:
(1) Certain foods prepared from hemp are legal.
(2) Previous studies have shown high levels of THC in some hemp products, sufficient to cause a positive urine drug test.
(3) The Drug Enforcement Agency (DEA) has worked to have producers greatly reduce the amount of THC in hemp products so that levels now are a fraction of that seen previously.
(4) If the Federal Government has its way any product containing THC would be declared a Schedule I Controlled Substance.
(5) Some products using Hemp such as hemp beer do not have measurable levels of THC.
Approach to the evaluation of a claim of a positive urine test due to hemp product ingestion:
(1) Determine if the employer has a policy that prohibits ingestion of hemp oil or other hemp products as a condition for employment. Employees must be made aware of this policy.
(2) Identify the hemp product involved and determine its THC content.
(3) Determine if the amount ingested by the employee is sufficient to cause a positive urine drug test.
total amount of THC ingested =
= (grams of hemp product) * (THC content in micrograms per gram hemp product)
According to Leson et al, a daily dose of hemp products giving > 0.6 mg of THC may cause a positive urine drug test. However, the amount of hemp products that needed to be ingested was very large (125 mL of hemp oil with 5 micrograms per gram; or 300 grams of hulled seeds with 2 micrograms per gram).
According to Gustafson et al, ingestion of 0.39 to 0.47 mg THC per day resulted in a very low rate of positive urine drug tests (< 0.2%) while doses of 7.5 grams or more per day were commonly positive. However, testing involved all urine samples including those collected shortly after ingestion.
