Missouri Revised Statutes Title XXXVIII. Crimes and Punishment; Peace Officers and Public Defenders § 577.021. Chemical testing authorized--reasonable efforts to test required--admissibility

1. Any state, county or municipal law enforcement officer who is certified pursuant to chapter 590 may, prior to arrest, administer a chemical test to any person suspected of operating a vehicle, vessel, or aircraft or acting as a flight crew member of an aircraft while in an intoxicated condition or with an excessive blood alcohol content.

2. Any state, county, or municipal law enforcement officer who is certified under chapter 590 shall make all reasonable efforts to administer a chemical test to any person suspected of operating a vehicle or vessel involved in a collision or accident which resulted in a fatality or serious physical injury as defined in section 556.061.

3. A test administered pursuant to this section shall be admissible as evidence of probable cause to arrest and as exculpatory evidence, but shall not be admissible as evidence of blood alcohol content. The provisions of sections 577.019 and 577.020 shall not apply to a test administered prior to arrest pursuant to this section.