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What Happens if Urine Test Results in an OVI Case are Within the Margin of Error?

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Will a Court Consider Margins of Error in Urine Testing When a Defendant Faces an OVI Conviction?

An Ohio Court of Appeals has recently ruled that it will not consider a margin of error as reason to dismiss an OVI case unless conviction “created such a manifest miscarriage of justice that the conviction must be reversed and a new trial ordered.”  

In this case, the Defendant’s urine test results were just .02 over the limit, and the margin of error was .03. However, the court found that since the expert tested the sample twice and found it to be .02 over the limit each time, the margin of error should not be considered.  

The court did, though, give themselves an out to consider margin of errors in other cases where the facts demand it.  An example might be where an expert tests a sample multiple times and gets different results each time, including a result under the limit. 

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O.R.C. 4511.19(A)(1)(i)

In State v. Perdue, 2016-Ohio-4947, the Defendant was traveling in his vehicle and was stopped by police as the officer noticed the Defendant crossing the double-yellow line several times. The Defendant was arrested and charged with an OVI under O.R.C. 4511.19(A)(1)(i).

Under section 4511.19, a driver is considered “per se” impaired if his urine test shows a level of .238 or higher (concentration level of two hundred thirty-eight-thousandths (.238) of one gram or more by weight of alcohol per one hundred milliliters of urine).  

Here, the Defendant was convicted of OVI based, in part, on evidence of a urine test, which indicated an alcohol content of .24 — just barely (.02) over the limit. 


The Defendant appealed his conviction based on testimony at trial from an expert criminalist.  In his testimony, the criminalist stated that a urine test for alcohol has a margin of error of .03.  Because the Defendant’s result was just .02 over the limit, he argued, he should not have been convicted.

In his argument before the Court of Appeals, the Defendant reasoned that the legal limit was .238 and his alcohol content at the time of arrest could have been anywhere from .21 to .27.  It was possible that his actual alcohol content was below the per se level (.238) outlined in O.R.C. 4511.19(a)(1)(i).


The Court in Perdue cited in its opinion a case from the Ninth District Court of Appeals where a defendant was charged with possession of 500 grams of cocaine where the margin of error for the weighing of the cocaine was .5 grams. In State v. Troutman, 9th Dist. Lorain No. 12CA010223, 2013-Ohio-4559 the Court reasoned that when a criminalist testifies to a certain amount or weight; the Court will be inclined to believe the testimony and will not inquire into margins of error.

Relying on the ruling of the Ninth District, the Court in Perdue held that since the criminalist tested the Defendant’s urine sample twice, and both instances indicated a urine content of .24, then it would accept the criminalists findings that the Defendant had an alcohol content required to be charged under O.R.C. 4511.19(a)(1)(i).  The court would not consider the possible margin of error in determining whether the Defendant tested over the limit. 


The Court in Perdue did leave itself room to overturn a conviction when considering margins of error in urine tests. The Court said it will rely on the standard set forth in State v. Martin (1983), 20 Ohio App.3d 172, 175, 485 N.E.2d 717. The Court will “review the entire record, weigh the evidence and all reasonable inferences, consider the credibility of witnesses and determine whether in resolving conflicts in the evidence, the jury clearly lost its way and created such a manifest miscarriage of justice that the conviction must be reversed and a new trial [be] ordered.”

A conviction under O.R.C. 4511.19(a)(1)(i) would need to be so contradictory of evidence presented, where margins of error in a urine test would include, that a court would conclude a “miscarriage of justice” occurred.  

If you have been charged with OVI under O.R.C. 4511.19(a)(1)(i) or any other related sections and have Columbus OVI attorneys about your case at 614-361-2804.

Written by Anthony Iori, Esq., Riddell Law Associate Attorney