Wash. Rev. Code § 46.52.065
Every coroner or other official performing like functions shall submit to the state toxicologist a blood sample taken from all drivers and all pedestrians who are killed in any traffic accident where the death occurred within four hours after the accident. Blood samples shall be taken and submitted in the manner prescribed by the state toxicologist. The state toxicologist shall analyze these blood samples to determine the concentration of alcohol and, where feasible, the presence of drugs or other toxic substances. The reports and records of the state toxicologist relating to analyses made pursuant to this section shall be confidential: PROVIDED, That the results of these analyses shall be reported to the state patrol and made available to the prosecuting attorney or law enforcement agency having jurisdiction: PROVIDED FURTHER, That the results of these analyses may be admitted in evidence in any civil or criminal action where relevant and shall be made available to the parties to any such litigation on application to the court.
RCW 46.52.065