In September, a Quest Diagnostics report revealed that many people are failing workplace drug use tests. The report studied the results of over 10.5 million workplace drug tests, and the greatest increase in drug use among employees was indicated by hair sample results. However, these results are contestable, because although the FDA approves the usage of hair samples for testing, the federal government does not consider hair samples as a reliable testing method for regulated programs. Proponents of hair testing posit that new hair cells absorb molecules of substances that circulate in blood, which create a permanent record in the hair as it grows. After dissolving the hair sample into solvents, GC/MS is used to classify drug particles and metabolites. Currently, the Department of Human Health and Services is in the process of evaluating the efficacy of hair testing and if it should be added to the federal employee screening process.
Generally, drug molecules are detectable in hair samples for up to 90 days, giving a more rounded indication of the employee’s lifestyle. However, due to various studies over the years that have proved that drug molecules are more easily absorbed by dark hair than light hair, there is a possible racial bias in using hair samples for drug use testing. Melanin plays a key role in the absorption rate of drug metabolites in hair, and dark-haired people who use various hairstyling products have hair that is more susceptible to being permeated by drug molecules. Hair testing cannot yet distinguish between drug metabolites from ingestion or from environmental exposure. For these purposes, some scientists are suggesting the use of hair testing for clinical and research purposes only.
Source: STAT News