Dear friend, Doctors and laboratories sometimes make mistakes, and sometimes their patient becomes victimized. In one study, primary care physicians engaged in the practice of adolescent medicine–nearly all of whom had incorporated UDT in their practice–lacked essential knowledge regarding proper specimen collection and validation, interpretation of positive and negative results, and the need for confirmatory testing. Only 12% of the physicians surveyed knew that oxycodone is not detectable by most opiate screening immunoassays; 40% of physicians knew that poppy seeds could produce a positive screen for opiates; and less than 50% of physicians knew the temporal limits of detection of Δ9-tetrahydrocannibinol in the urine of regular marijuana users. In a study of emergency department physicians, only 5% correctly identified what substances were detectable by the UDT method used in their hospital, and nearly three quarters of doctors are fallible. I suggest a retest at a different facility. Best regards, Elliott