Blood and Urine extraction for drug testingToxicology is the study of harmful effects of chemicals on biological systems. It is a branch of pharmacology that incorporates many areas of knowledge including pharmacology, analytical and organic chemistry, physiology, and pathology. 

The Toxicology Laboratory analyzes biological specimens for the presence of alcohol, drugs and other toxic compounds as a part of postmortem medicolegal investigations of the Westchester County Medical Examiner's Office. The Medical Examiner’s Office uses information generated by the toxicology laboratory when determining the manner and cause of death of an individual. Through the application of toxicological and pharmacological principles, the toxicologists interpret the test results in order to assist with the formation of conclusions regarding the circumstances of the death. 

The laboratory provides human performance testing services to local, county and state law enforcement agencies within the county associated with the charges of driving while under the influence of alcohol (DWI) and driving while under the influence of drugs (DUID) arrests. Human performance testing refers to the testing of individuals for any impairment of their ability to operate motor vehicles due to the presence of drugs or other performance impairing substances. Laboratory testing results may determine impairment due to alcohol or confirm impairment by other drugs and substances.

Laboratory personnel also provide human performance testing consultations and testimony for breath alcohol testing conducted in the county by law enforcement agencies. 

On occasion, toxicological investigations are conducted for county health facilities.