A hospital blood-alcohol result and a police-directed test can show different numbers without either report necessarily being wrong. Before drawing a conclusion, compare the actual specimens, units, collection times and methods. A hospital may report serum or plasma ethanol, while a forensic report may measure whole blood; those values are not automatically interchangeable. A published comparison found differences between serum, plasma and whole blood, but it does not supply a reliable conversion for an individual case. Penetar and colleagues, Comparison Among Plasma, Serum, and Whole Blood Ethanol Concentrations.
| Check on both reports | Why it matters |
|---|---|
| Specimen and analyte | Identify whether each number is ethanol in whole blood, serum or plasma. A label such as “blood alcohol” may not answer that question. |
| Units and reported value | Compare the units before comparing the numbers. California’s ordinary DUI blood threshold under Vehicle Code § 23152(b) is 0.08 percent by weight, defined as grams of alcohol per 100 milliliters of blood. A serum or plasma value needs case-specific interpretation before anyone treats it as that statutory blood measure. |
| Collection time | Record when each specimen was drawn, rather than relying on the time the result appeared in a chart. Two samples collected at different times need not produce the same result. Section 23152(b)’s three-hour provision creates a rebuttable presumption for a qualifying chemical test; neither report alone settles the alcohol level at the time of driving. |
| Method and sample identity | Ask which laboratory method produced each result and whether the specimen identifiers match the person and draw at issue. The written procedures for a forensic alcohol method include calibration and quality-control procedures under 17 CCR § 1220. The actual hospital method must be checked from its own laboratory records. |
Does a difference make either result inadmissible?
No automatic rule follows from the difference. The hospital test’s treatment purpose does not, by itself, establish that its result is invalid or that every forensic testing rule governed that test. California’s published People v. Williams decision explains that compliance with forensic testing regulations can establish a foundation, but other proof of reliable equipment, proper administration and a competent operator can also do so. The significance of a particular gap or discrepancy depends on the reports and the evidence offered to explain them.
If you have both reports, bring them, their collection times and the charge paperwork to counsel. Ask counsel to obtain the relevant specimen, laboratory-method and quality-control records for the result the prosecution relies on, and to assess whether expert comparison is needed. Penal Code § 1054.1 governs prosecution disclosure of qualifying evidence and scientific-test reports within its possession or knowledge limits; Vehicle Code § 23158(c) permits a person tested at an officer’s direction to request full information concerning that test. For the separate question of how police may obtain a hospital treatment record, see that guide.
The Law Offices of David S. Chesley can review the reports and the charge with you. Call (800) 755-5174.