306.117. 1. Upon the trial of any person for violation of any of the provisions of section 306.111 or 306.112 the amount of alcohol or drugs in the person's blood at the time of the act alleged as shown by any chemical analysis of the person's blood, breath, urine, or saliva is admissible in evidence and the provisions of subdivision (5) of section 491.060 shall not prevent the admissibility or introduction of such evidence if otherwise admissible. Evidence of alcohol in a person's blood shall be given the following effect:
(1) If there was five-hundredths of one percent or less by weight of alcohol in such person's blood, it shall be presumed that the person was not intoxicated at the time the specimen was obtained;
(2) If there was in excess of five-hundredths of one percent but less than eight-hundredths of one percent by weight of alcohol in such person's blood, the fact shall not give rise to any presumption that the person was or was not intoxicated, but the fact may be considered with other competent evidence in determining whether the person was intoxicated;
(3) If there was eight-hundredths of one percent or more by weight of alcohol in the person's blood, this shall be prima facie evidence that the person was intoxicated at the time the specimen was taken.
2. Percent by weight of alcohol in the blood shall be based upon grams of alcohol per one hundred milliliters of blood.
3. A chemical analysis of a person's breath, blood, urine, or saliva, in order to give rise to the presumption or to have the effect provided for in subsection 1 of this section, shall have been performed as provided in sections 306.111 to 306.119 and in accordance with methods and standards approved by the department of health and senior services.
4. The provisions of this section shall not be construed as limiting the introduction of any other competent evidence bearing upon the question whether the person was intoxicated or under the influence of a controlled substance, or drug, or a combination of either or both with or without alcohol.