Toxicologic analysis is an integral part of death investigation, and the use or abuse of an unsuspected substance belongs in the differential diagnosis of patients who have a sudden, unexpected change in their condition. History and physical findings may alter suspicion that intoxication played a role in a patient's decline or death, but suspicions cannot be confirmed and is performed, analysis unless toxicologic no toxicologic analysis is possible unless someone collects the proper specimens necessary for analysis. In a hospital autopsy the only specimens that can rightfully be collected are those within the restrictions stated in the autopsy permit. Autopsies performed by the medical examiner do not have these restrictions. Sometimes the importance of toxicologic testing in a case is not evident until days or weeks after the change in the patient's status, thus retaining the appropriate specimens until investigation of that case has ended is important. Proper interpretation of toxicologic findings requires integrating the clinical setting and findings with the toxicologic results in a way that makes medical sense. If called upon to testify concerning findings, answer the questions truthfully, politely, and in a way that is understandable to someone who has no special training in toxicology.