How Calibration Problems Create Inaccurate DUI Chemical Test Results

Most people assume that DUI chemical test results are accurate because they come from scientific devices. The truth is far more complicated. Breath and blood testing machines used in Ohio OVI cases require strict calibration, routine maintenance, and precise procedures to produce reliable results. When any part of that system fails, the outcome can be misleading and potentially devastating for the person accused. Our Cleveland criminal defense lawyers at Patrick M. Farrell Co. L.P.A. represent clients throughout Cuyahoga County and Northeast Ohio who face OVI charges built on questionable chemical test results. Understanding how calibration failures occur is the first step in building a strong defense.

OVI charges under O.R.C. § 4511.19 rely heavily on numerical test results. However, numbers alone do not prove impairment, and faulty machines can produce readings that suggest intoxication even when a driver is sober or only mildly impaired. For this reason, challenging calibration and maintenance problems is a critical defense strategy by our Cleveland drunk driving (DUI/OVI) defense lawyers.

Why Calibration Matters in Ohio DUI Chemical Testing

Ohio breath testing machines measure alcohol concentration in a person’s breath by generating a reading based on chemical reactions or infrared absorption. These devices must be calibrated regularly to ensure accuracy. Without proper calibration:

• Test results may drift over time
• Even minor hardware problems can cause significant errors
• Machines may read higher or lower than reality
• Breath samples may be misinterpreted

Ohio law requires breath testing equipment to meet strict regulations established by the Ohio Department of Health. When these standards are not followed, the results may be unreliable and subject to suppression in court.

Common Calibration Problems That Cause Inaccurate Results

Several factors can create false positives or inflated readings during DUI chemical testing. Our legal team frequently identifies these issues while reviewing discovery in OVI cases.

1. Failure to Perform Regular Calibration Checks

Ohio’s breath testing machines must be calibrated at specific intervals. When law enforcement agencies fail to follow these requirements, the device may operate inaccurately for weeks or months before anyone notices. This gap can affect every test performed during that time.

2. Improperly Performed Calibration Procedures

Even when officers complete calibration checks, they must follow detailed protocols. Mistakes include:

• Using expired or contaminated calibration solutions
• Incorrect temperature settings
• Misreading reference standards
• Skipping steps in the testing sequence

These errors undermine the reliability of the entire machine.

3. Machine Maintenance Errors

Breath testing devices contain sensitive sensors, pumps, software programs, and electrical components. Maintenance problems may include:

• Software updates not installed
• Aging sensors producing inconsistent readings
• Clogged or dirty internal components
• Faulty wiring or unstable electrical supply

These issues are common but often overlooked during routine inspections.

4. Infrared or Chemical Sensor Malfunctions

Breath testing machines rely on chemical and infrared sensors to detect ethanol. When these sensors fail or deteriorate, the machine may:

• Detect non-alcohol substances as ethanol
• Amplify actual alcohol concentration
• Generate inconsistent readings across multiple samples

If the device logs unexplained spikes or irregularities, that is a red flag for the defense.

5. Temperature Errors

Breath testing requires strict temperature control. If the testing chamber is too warm or too cold, readings can be artificially inflated. Body temperature differences and environmental conditions can also affect the outcome.

Key takeaway: Even slight calibration deviations can produce results that appear scientifically accurate but are legally unreliable.

The Role of Police Officer Procedures in Chemical Test Accuracy

Machine calibration is only part of the equation. Officers must follow specific procedures during each test to maintain accuracy. Common problems include:

• Not observing the driver for the required observation period
• Allowing mouth alcohol contamination from burping or regurgitation
• Improperly instructing the driver on how to blow into the machine
• Using equipment without verifying recent calibration checks

When officer errors occur, the resulting BAC number may not reflect a driver’s actual level of impairment.

Blood Test Calibration Errors and Lab Mistakes

Breath tests are not the only concern. Blood tests used in OVI cases also require strict calibration and precise laboratory handling. Problems may include:

• Broken or expired blood vials
• Incorrect preservative ratios
• Calibration drift in gas chromatography machines
• Sample contamination
• Poor chain of custody documentation

Inaccurate blood test results may appear scientific, but laboratory errors can change the outcome of an entire case.

How Prosecutors Use Chemical Test Results in Court

Prosecutors often treat chemical test results as the strongest evidence of guilt. These results drive:

• Charging decisions
• Arraignment strategy
• Plea negotiations
• Trial preparation

However, during discovery our legal team reviews calibration logs, maintenance records, training certifications, and lab documentation to uncover weaknesses the prosecution hopes to avoid highlighting.

How Patrick M. Farrell Co. L.P.A. Challenges Faulty Test Results

Our Cleveland criminal defense lawyers use a comprehensive strategy to challenge inaccurate chemical testing. This may include:

• Filing motions to suppress invalid test results
• Examining calibration logs for missing entries or improper procedures
• Analyzing officer training and compliance records
• Reviewing maintenance documents for unresolved issues
• Consulting independent forensic toxicologists
• Highlighting inconsistencies between test results and officer observations

If you're looking for a Cleveland drunk driving defense lawyer near me who understands the science behind breath and blood testing, our team provides the technical and legal experience needed to defend against flawed chemical evidence.

Proper Calibration Is Essential for Fairness in OVI Cases

Chemical test results play a major role in Ohio OVI prosecutions, but inaccurate machines and flawed procedures can lead to wrongful charges. Breath and blood testing devices are only as reliable as the people who maintain and operate them. When calibration problems occur, the results should be challenged aggressively to ensure fairness and accuracy. The legal team at Patrick M. Farrell Co. L.P.A. represents clients in Cleveland, Lakewood, and throughout Northeast Ohio with a detailed understanding of chemical test procedures and a commitment to exposing errors that create reasonable doubt. Your defense deserves a team that knows how to uncover the flaws behind the numbers.

If you’ve been arrested in Cleveland, Lakewood, or anywhere in Northeast Ohio, don’t wait. Call Patrick M. Farrell Co. L.P.A. at (216) 661-5050 or request a free consultation now. A strong defense begins by questioning the accuracy of the evidence used against you.

Text or Call: (216) 661-5050 • Contact: Submit a Request • Email: cindy@patfarrelllaw.com

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