Urinalysis to Determine Blood Alcohol in DUI Investigations

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To avoid or at least minimize this problem of urine accumulation in a DUI case, it is necessary to have the subject void his bladder prior to producing a sample. After a short wait, perhaps 15 or 20 minutes, he should then be able to produce additional urine for analysis.

Certainly, urinalysis is a completely undependable DUI testing procedure where voiding has not taken place 15 or 20 minutes before the sample is obtained. In many jurisdictions today, this voiding is a legal prerequisite for admissibility of results in a DUI trial. (See, e.g., State v. Donaldson, 425 N.W.2d 531 (Neb. 1990), reversing a conviction where the sample was taken from the DUI defendant 33 minutes after voiding.) Where it is not, however, counsel in a DUI trial should move to suppress the results of urinalysis where the defendant was not required to void his bladder and wait before giving a sample. The reason for this is set forth by the American Medical Association in its publication entitled Alcohol and the Impaired Driver: A Manual on the Aspects of Chemical Tests for Medicolegal Intoxication (1968: American Medical Association, 535 North Dearborn Street, Chicago, Illinois 60610):

"If a person starts drinking with the bladder full of urine, or has not voided for some hours, while the blood level of alcohol is decreasing, the level in the bladder may change more slowly than that of the blood as the latter rises or falls. This discrepancy can be overcome by having the subject empty his bladder and by taking the sample of urine after 20 minutes."

In fact, obtaining only one sample of urine after a voiding is considerably less accurate than obtaining two samples isolated in time after a voiding. Although this is rarely done in DUI investigations by law enforcement agencies, counsel should at least bring out for the jury the fact that the American Medical Association, in the same publication, states (at p.71) that collection of "duplicate samples with a time lapse of at least 20 minutes and complete voiding of the bladder so that no residual urine is retained is recommended."

The AMA's recommendation has been endorsed by criminalists employed by the largest state prosecuting agency in the country. In an article entitled Blood Alcohol Concentration Determined from Urine Samples as a Practical Equivalent or Alternative to Blood and Breath Alcohol Tests, 30 Journal of Forensic Sciences 194 (1984), Biasotti and Valentine, two criminalists with the Bureau of Forensic Sciences, California Department of Justice, concluded after considerable research and experimentation that "[a] second urine 'sample' taken at least 20 minutes to one hour after first voiding the bladder should be used to determine an equivalent percent BAC." These criminalists went further, however:

"To validate further the accuracy of a BAC determined from the urine sample taken after first voiding the bladder, and to determine if the BAC has increased or decreased during the time between voiding and the second urine "sample," at least a 30-ml portion of the "void" urine sample should be collected, analyzed, and reported together with the second urine "sample" results."

Even where the proper voiding procedures were followed, urinalysis is at best a relatively undependable method of determining blood alcohol in DUI cases. Any honest prosecution expert witness, if pressed, will have to admit that of the three analytic procedures, urinalysis is generally considered a distant third in reliable accuracy. If he refuses to, his attention - and that of the jury - should be directed to a booklet entitled Highway Safety Program Manual No. 8. Published by the National Highway Traffic and Safety Administration of the U.S. Department of Transportation, the manual sets forth proposed regulations for the development and operation of alcohol testing programs. This is in accordance with Chapter 4 of Title 23 of the U.S. Code, known as the Highway Safety Act of 1966, wherein uniform highway safety standards are to be established. The following recommendations from that manual will be of interest to the jury:

"Because of various problems in the interpretation of the results of analysis of urine for alcohol which cannot be readily overcome in law enforcement practice, urine analysis to determine equivalent alcohol concentration in blood is discouraged, except under strictly controlled conditions (e.g., hospitalized subject), or for the limited purpose of demonstrating recent ingestion of alcohol. Chemical tests of blood or breath are preferred."