(1) Evidence that there was, at that time, five hundredths of one percent or less, by weight, of alcohol in his or her blood, is prima facie evidence that the person was not under the influence of alcohol;
(2) Evidence that there was, at that time, more than five hundredths of one percent and less than eight hundredths of one percent, by weight, of alcohol in the person's blood is relevant evidence, but it is not to be given prima facie effect in indicating whether the person was under the influence of alcohol;
(3) Evidence that there was, at that time, eight hundredths of one percent or more, by weight, of alcohol in his or her blood, shall be admitted as prima facie evidence that the person was under the influence of alcohol.
(b) A determination of the percent, by weight, of alcohol in the blood shall be based upon a formula of:
(1) The number of grams of alcohol per one hundred cubic centimeters of blood;
(2) The number of grams of alcohol per two hundred ten liters of breath;
(3) The number of grams of alcohol per sixty-seven milliliters of urine; or
(4) The number of grams of alcohol per eighty-six milliliters of serum.
(c) A chemical analysis of a person's blood, breath or urine, in order to give rise to the presumptions or to have the effect provided for in subsection (a) of this section, must be performed in accordance with methods and standards approved by the state division of health. A chemical analysis of blood or urine to determine the alcohol content of blood shall be conducted by a qualified laboratory or by the state police scientific laboratory of the criminal identification bureau of the West Virginia state police.
(d) The provisions of this article do not limit the introduction in any administrative or judicial proceeding of any other competent evidence bearing on the question of whether the person was under the influence of alcohol, controlled substances or drugs.