In any prosecution for a violation of provision (ii) of subsection A of § 46.2-341.24, the amount of alcohol in the blood of the accused at the time of the alleged offense as indicated by a chemical analysis of a sample of the suspect's blood or breath to determine the alcoholic content of his blood in accordance with the provisions of §§ 46.2-341.26:1 through 46.2-341.26:11 shall give rise to the following rebuttable presumption: if there was at that time 0.08 percent or more by weight by volume of alcohol in the accused's blood or 0.08 grams or more per 210 liters of the accused's breath, it shall be presumed that the accused was under the influence of alcoholic intoxicants.

If there was at that time less than 0.08 percent by weight by volume of alcohol in the accused's blood or 0.08 grams or more per 210 liters of the accused's breath, such fact shall not give rise to any presumption that the accused was or was not under the influence of alcoholic intoxicants, but such fact may be considered with other competent evidence in determining the guilt or innocence of the accused.