DMT Margin of Error

Updated: May 31

The Datamaster DMT can differ as much as 4% from an internal test standard and still not trigger an error code.

The accepted margin of error for the Datamaster DMT, published by manufacturer NPAS, and acknowledged by the Iowa Department of Public Safety, is +/- 5% or .004 grams ethanol per 210 L breath whichever is greater. Iowa Dept Public Safety SOP BAC-14 Para. 5.4.5. Available at: (last visited June 13, 2016).

The margin of error may matter to a jury if a test result is near the presumptive legal level of intoxication and there is no evidence of other intoxicants present in the test subject’s body.

For example, if a test subject admits to a valid prescription for hydrocodone and indicates that they took medication in the last 24 hours, the prosecution may argue that the margin of error is meaningless because the mixture of alcohol and drugs may still impair a test subject and motorist below the presumptive level of intoxication. This may require expert testimony to contest prosecution witnesses, e.g., police, who attempt to speak to subjects beyond their expertise, like medicine or other sciences.

If you or a loved one has been arrested for OWI (DUI) in the State of Iowa, contact us for a free initial consultation.

However, remember that a blog is not legal advice and sending unsolicited information to a lawyer over the Internet does not establish an attorney-client relationship.

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