Breath Tests

Breath Tests in Ohio OVI Cases

Breath tests are often treated as the most definitive piece of evidence in an OVI case. A number appears. The case feels decided.

That confidence is overstated.

A breath test is not a direct measurement of intoxication. It is an estimate based on assumptions about how alcohol is absorbed, processed, and expelled from the body, combined with the performance of a machine operated by a human being. When any of those assumptions are off, the result can be misleading.

That happens more often than most people realize.

Breath tests matter, but they are not infallible. How the test was requested, administered, calibrated, and recorded matters just as much as the number itself.

What a Breath Test Is Supposed to Measure

Breath testing is based on the theory that alcohol concentration in a person’s breath correlates to alcohol concentration in their blood. Under controlled conditions, that relationship can exist.

That is the theory.

In practice, the breath test relies on a long chain of conditions being met. The machine must be properly calibrated and maintained. The operator must follow required observation periods and procedures. The subject must provide a sample that meets technical requirements. The test must occur at a point in time that accurately reflects blood alcohol concentration.

When those conditions are not met, the number loses reliability.

Breath tests do not measure impairment. They do not measure driving ability. They measure a snapshot taken under imperfect circumstances.

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Why Breath Test Results Can Be Misleading

Breath test results are affected by timing, physiology, and procedure. Alcohol absorption is not instantaneous or uniform. A person’s blood alcohol level can be rising or falling at the time of the test. Medical conditions, diet, reflux, and recent alcohol consumption can all influence results.

The machine does not account for those variables. It assumes a standardized body responding in a standardized way.

That assumption often does not hold.

Small procedural errors can also have outsized effects. Observation periods, mouth alcohol contamination, improper instructions, or mechanical issues can all skew results. Those issues are not always visible on the surface but become important when the test is examined closely.

How Breath Tests Are Used in an OVI Case

Breath test results are typically presented as objective proof. They are used to support charges, license suspensions, and enhanced penalties.

They are not evaluated in isolation.

Breath tests are reviewed alongside the traffic stop, field sobriety testing, officer observations, and video evidence. When those pieces do not align, the breath test result deserves scrutiny rather than blind acceptance.

A careful review looks at whether the test was required, whether it was properly administered, and whether the result actually supports the conclusions being drawn.

Those questions often change the posture of a case.

Breath Tests and Chemical Testing as a Whole

Breath tests are one category of chemical testing. Blood and urine testing raise different issues and follow different rules.

We address chemical testing more broadly in the Chemical Test Overview, and we address blood and urine testing separately because the legal and scientific considerations are not the same.

Understanding where a breath test fits in that larger framework matters when evaluating options and consequences.

Talking Through Your Breath Test Result

Most people are told they “failed” a breath test and are left to assume that ends the conversation. It does not.

A meaningful discussion looks at when the test occurred, how it was conducted, what the surrounding evidence shows, and how the result is likely to be interpreted later. That context matters more than the number alone.

Understanding that context makes it easier to decide what matters, what does not, and how to move forward.

Talk to an OVI attorney about your breath test result.

Portable Breath Tests in Ohio and What They Actually Mean

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Know Your Rights Before Compliance Becomes Evidence: OVI Pocket Guide

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Officers oftentimes make up the rules instead of following standardized procedures

Field sobriety tests are defended on the ground that they are standardized. Officers invoke training. Prosecutors invoke the manual. The promise is that the test being described is the test that was validated. That promise often fails. In Ohio OVI investigations , officers routinely rely on techniques the manual never endorses. When asked to justify those techniques, the response is not science or training. It is silence. The absence of authority matters, especially when the

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