Several prescription pain medications, poppy seeds and lactic acidosis may result in false positive toxicology test screenings for opioids such as morphine, states the National Institutes of Health. An understanding of a patient’s medical history is required to anticipate false-positives, notes the University of Illinois College of Pharmacy.
To anticipate false positives and to differentiate between legitimate drug use and drug abuse, an extensive medication history that includes prescription, over-the-counter and herbal medications should be obtained from the patient, says the University of Illinois College of Pharmacy. In addition, as lactate dehydrogenase and lactate may interfere with analytic procedures for the detection of opioids, additional urine testing should be undertaken for individuals who are at risk of lactic acidosis, such as those with diabetes mellitus, liver disease or a toxin ingestion, states the National Institutes of Health.
While heroine detection can be facilitated due to its unique metabolites, some synthetic drugs, such as oxycodone, is often undetected in urine toxicology screening, so an understanding of synthetic and semisynthetic opiates is required for accurate screening. Methods used to falsify drugs-of-abuse testing include tampering with the sample, such as by adding water and masking agents, obtaining clean urine or by dilution from ingesting large quantities of water or detoxification kits, states the National Institutes of Health.