The donor’s specimen sat out all weekend on the countertop unrefrigerated, is it still okay for testing?
Yes, but we advise testing an unrefrigerated specimen within seven days of collection. It is known that the concentrations of some drugs and their metabolites decrease gradually in room temperature urine. Refrigeration can slow this process somewhat and freezing will preserve a sample indefinitely. Usually the decrease is not dramatic, but in the worst-case scenario, a borderline positive level might drop below the detection threshold. An unrefrigerated specimen would never cause a false positive, with one important exception. Alcohol may form in unrefrigerated urine due to fermentation, if the urine sugar (glucose) is elevated, such as in diabetes. We recommend that alcohol screens be shipped promptly, and we check for the presence of glucose in all positives.
