When a DUI case involves injury or property damage, the stakes for the defense and prosecution are at their highest. One of the most technical battlegrounds in these trials is the admissibility of breath test results that are labeled "Volume Not Met."

A recent court ruling has clarified that even "incomplete" breath samples can be used to establish that a defendant's breath alcohol level was above the legal limit—if the prosecution follows the correct scientific path.

1. The Challenge: What is a "Volume Not Met" Sample?

Modern breathalyzers (like the Intoxilyzer 8000) generally require a minimum volume of air—usually 1.1 liters—to ensure they are measuring "deep lung air" (alveolar air), which provides the most accurate correlation to blood alcohol.

When a subject fails to provide this volume, the machine records the result but flags it as "Volume Not Met." Defense attorneys often file a Motion to Exclude these results, arguing they are scientifically invalid.

Why the Motion was Denied

In this recent case, the court denied the motion to exclude the results from four "Volume Not Met" samples. The court found that:

• Consistency is Key: Having four separate samples provided a consistent data set that allowed an expert to form a reliable opinion.

• Scientific Conservatism: Toxicology experts can demonstrate that "Volume Not Met" samples typically underestimate actual blood alcohol levels. Because the air comes from the upper respiratory tract rather than deep in the lungs, the alcohol concentration is actually lower than it would be in a full sample.

2. Expert Testimony: Meeting the "Gatekeeper" Standards

To admit these results, the prosecution's expert must satisfy the modern standard for expert testimony (often the Daubert standard). The court ruled that the expert's opinion met these three critical requirements:

3. The "Common Law Predicate" vs. Statutory Presumption

Perhaps the most significant legal distinction in this ruling is how the evidence is introduced.

The Statutory Shortcut

Under typical DUI laws (Implied Consent), if a test is performed perfectly according to administrative rules, the state gets a "Presumption of Impairment." This means if you are at $.08$ or higher, the law presumes you were impaired without further proof.

The Common Law Path

When a test has technical issues (like "Volume Not Met"), the state can still admit the results via the Common Law Predicate. This involves:

1. Proving the machine was in good working order.

2. Proving the operator was qualified.

3. Providing expert testimony to explain the results.

The Catch: Admission under the common law predicate does not trigger the presumption of impairment. The jury can see the $.08+$ number, but the judge will not instruct them that they must presume the defendant was impaired. The prosecution must still prove impairment through other evidence (driving pattern, field sobriety tests, etc.).

Conclusion

This ruling is a double-edged sword. It allows "incomplete" breath evidence into trial, but it also strips away the powerful legal presumption that usually accompanies a high breathalyzer reading. It places the burden squarely on expert testimony and the overall facts of the case.