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Psychemedics Record: No False Positives
We participate in blind-sample and proficiency testing to measure our ability to correctly identify
drugs and avoid false positives. We have participated in these blind sample and proficiency
programs for over fifteen years and have not had a false positive result.
In blind sample testing, a third party sends Psychemedics hair samples containing
particular drugs, and the goal for us is to test and correctly identify the drugs in each of the
samples. We have been tested by the National Institute of Standards and Technology, the
International Society of Hair Testing, and Walsh & Associates, and have achieved 100% accuracy.
Psychemedics also has an ongoing blind sample program, in which forensic toxicologists send
samples that are blind to us, and we test them and report the results through our Quality Assurance
department.
In proficiency testing, a third party sends hair samples to Psychemedics, and the goal is to
correctly identify and quantify the drugs in the hair. We participate in proficiency testing programs
conducted by ARVECON GmbH, the National Laboratory Certification Program, and the
International Society of Hair Testing.
We have passed all of these tests, and have not had a false positive result.
We also avoid false positives because of the following aspects of our testing process: 1) We
use mass spectrometry to identify drugs by their unique molecular fingerprints, so substances
cannot be “mistaken” for drugs. By contrast, urinalysis testing has, for example, in the past
mistaken poppy seed ingestion for the presence of opiate drugs. 2) We use a distinct barcode for
each sample, which we scan at every step to make sure we are testing the correct sample at all
times. 3) If the donor challenges the result by claiming it’s a false positive, we can collect a new
sample for repeat analysis. This is a unique advantage of hair testing, and allows us to provide the
appropriate and accurate rate of the positivity of drug classes.