A new study by Quest Diagnostics shows that hair-based drug tests reveal far more workplace drug users. Reason: Hair testing can identify usage going back up to three months, while urine testing is best at identifying drugs taken within the past three days.
Quest says its hair tests found cocaine in 32 of every 1,000 tests, while urine tests found cocaine in three of every 1,000 tests. Note: Hair tests cost about twice as much.
Both tests show workplace drug use on the decline. Hair tests show a 36% decline in cocaine use since 2005, while urine tests show a 57% decline. Marijuana was found in 2% of Quest’s tests in the first half of 2009, down from 2.5% in 2005.