Hannah Knowles

“serum ethanol concentrations are always higher than a blood alcohol concentration.”

Explains the basis for converting the hospital serum result to a whole-blood range.

“And so our results for this calculation are always expressed in a range to ensure that that individual's actual blood alcohol concentration lies somewhere between the range that we provide.”

States the witness's qualification that retrograde extrapolation produces a range rather than a single value.

“That based on the 93 milligrams per deciliter value that was obtained at Good Samaritan, that the blood alcohol concentration for that individual at 12:45 a.m. could be between 0.14 and 0.28%.”

Gives the retrograde range calculated from the hospital result.

Knowles described her forensic-toxicology education, State Police Crime Lab role, laboratory accreditation, and proficiency testing.

“But the results that I started from, I don't have any direct knowledge on their accuracy or reliability.”

Knowles qualified the foundation for her calculations by distinguishing it from the external hospital test result.

“Correct. I have no direct knowledge of the accuracy or reliability. My calculations are solely based on the results of the Good Samaritan lab.”

Knowles says she relied on the reported Good Samaritan result while lacking direct knowledge of that laboratory's accuracy or reliability; the testimony does not itself establish that the reported result was erroneous.

“It certainly is. .28 is double .14.”

The prosecution's own expert concedes the extraordinary width of the BAC range, undermining the precision of the calculation.

“The foundation of my calculations would be incorrect. I would need to perform different calculations or factor in the information as it would become available and issue a different report.”

Knowles says that, under the hypothetical of alcohol consumption after 12:45 a.m., the foundation of her calculations would be incorrect and she would need different calculations or a revised report; she did not characterize the existing analysis as simply collapsing.

“The conversion factors come from published studies involving individuals that consumed alcohol, had samples collected from them, and their whole blood and their serum alcohol concentrations were compared.”

Reinforces the scientific basis of the conversion factors challenged on cross.

“Less than 5%. The vast majority of alcohol is eliminated from the body by an enzyme that breaks it down from alcohol into carbon dioxide and water.”

Minimizes the defense's line of questioning about bladder elimination affecting BAC calculations.

“That range is intentionally wide to ensure that the actual blood alcohol concentration lies somewhere between it. It's intending to account for a lot of the factors that we've been discussing.”

Reframes the wide 0.14–0.28% range as conservative methodology rather than unreliable science.