In many states blood alcohol content tests serve as a standard tool for law enforcement. BAC testing measures alcohol levels in a person’s system through blood samples. BrAC testing using an evidential breath alcohol testing device is also commonly used in law enforcement and is the predominate testing method in the workplace. Regarded as highly reliable and defensible in a court of law, errors can occur in certain situations.
Many factors influence the accuracy of these tests, ranging from device calibration to human error. Understanding errors and invalid results in BrAC testing helps breath alcohol technicians (BATs) and subjects ensure fair and accurate testing processes. Small mistakes in procedure or maintenance can lead to significant discrepancies in the final reading.
Environmental factors such as temperature and radio-frequency interference also affect accuracy. Also ambient air could play a role. Many instruments conduct what is called an Air Blank test during the test. Sometimes even before the subject blows into the instrument. If the device detects alcohol in the air (sometimes conducting two Air Blanks), the device will not allow the BAT to continue with the test. The BAT will then need to move to another room or area to try again. This safeguards the individual and helps maintain the integrity of the testing process.
BAC and BrAC Testing
Blood Alcohol Concentration (BAC) and Breath Alcohol Concentration (BrAC) are distinct measurements used to determine the amount of alcohol in an individual’s system. BAC refers to the percentage of alcohol present in a person’s bloodstream and is typically measured through blood tests. BrAC measures the concentration of alcohol in the breath, which is a faster method of estimation.
Breathalyzers measure BrAC because alcohol content in the breath correlates with alcohol levels in the blood due to the way alcohol metabolizes in the body. When someone consumes alcohol, it goes into the bloodstream but also into the lungs through the process of gas exchange. Breathalyzers analyze this expelled breath by using sensors, such as infrared spectroscopy or electrochemical fuel cells, to gauge the alcohol concentration in the air sample.
Insufficient Breath Volume Affects Test Results
The subject must blow hard and long enough to provide deep lung air for an accurate measurement. Shallow breaths often result in a reading that does not reflect true blood alcohol concentration. Most breathalyzers will display an error code, notifying the operator if the air volume is not sufficient. This is sometimes referred to as “Minimum Volume”.
Test operators must instruct subjects on how to provide a continuous and strong breath sample. If the breath flow stops too soon, the device cannot capture the necessary sample for analysis. Proper technique ensures that the sensor receives deep-lung air, where alcohol exchange takes place.
Mouth Alcohol Residue Creates False Positives
Mouth alcohol residue is a common cause of false positive results in breath alcohol tests. This can occur when substances such as mouthwash, breath spray, or certain medications containing alcohol temporarily linger in the oral cavity. Instead of measuring the alcohol content from deep lung air, which accurately reflects blood alcohol concentration, the testing device mistakenly detects the concentrated vapor from these substances.
To address this issue, it is essential to follow proper testing protocols. In a workplace testing situation, a 15-minute wait period is observed immediately after a positive screening test and before a final confirmation test. This mandatory wait period ensures that any residual mouth alcohol dissipates that may have been present during the screening test. Individuals should avoid using alcohol-based products (including medication) just before testing to minimize the risk of contamination and ensure accurate results. However, if it is truly residual mouth alcohol, the alcohol will dissipate and be eliminated from the mouth within the 15-minute period. This is why the 15-minute waiting period was established. If the instrument detects alcohol after the 15-minute period, that indicates that alcohol is running in the blood stream and the final outcome is a positive test result.
Calibration Issues Often Cause Inaccurate Readings
Calibration issues can significantly undermine the reliability of breathalyzer results, potentially leading to inaccurate readings and compromised testing outcomes. Without regular checks and proper maintenance, a breathalyzer might fail to detect alcohol levels accurately, either displaying false positives or missing critical results.
New breathalyzers have advanced technology to mitigate these risks. Features such as automated calibration reminders, and enhanced sensors, ensure a higher degree of precision. Breathalyzers found on NHTSA’s conforming products list of evidential breath testers will ensure the dependability of these devices, safeguarding the integrity of alcohol testing programs and reducing the impact of potential calibration errors.For all DOT alcohol testing, specific training to calibrate and conduct accuracy checks is required.
Environmental Factors
Environmental factors, such as extreme temperatures or radio frequency interference, have the potential to impact device performance. However, modern breathalyzers possess advanced technologies designed to mitigate these challenges. They incorporate temperature sensors to monitor the operating environment and will prevent testing if conditions exceed the approved range.
Enhanced shielding mechanisms help reduce the effects of interference from external radio frequencies, ensuring the devices maintain accuracy even in challenging conditions. These innovations enable modern breathalyzers to deliver reliable and consistent results, adapting effectively to environmental factors that could otherwise compromise their functionality.
Health Conditions Mimic Intoxication Signals
Certain health conditions, such as diabetes, can produce signals that mimic intoxication, potentially leading to false-positive readings on over-the-counter or non-evidential breath tests. Diabetics experiencing ketoacidosis may emit acetone, a substance that passes for alcohol by some devices.
Using an evidential-quality breathalyzers eliminates these errors and are able to differentiate between alcohol and other substances. With multiple detection technologies and rigorous calibration protocols, these devices enhance accuracy and reduce the risk of misinterpretation, ensuring fair evaluation regardless of underlying health conditions.
However, 49 CFR Part 40.231(b)(4) has addressed this issue. For confirmation tests, an EBT must, among other capabilities, distinguish alcohol from acetone at the 0.02 alcohol concentration level. So, if the individual is a diabetic, the device that is used for DOT alcohol testing will not result in a positive alcohol test since the device is designed to only analyze alcohol such as Ethanol (ethyl alcohol), Methanol (methyl alcohol) and Isopropanol (isopropyl alcohol).
Improper Operator Training
Improper operator training is one of the main sources of invalid results in BrAC testing. When operators do not have proper training, they may lack the detailed knowledge and skills required to follow procedures precisely, leading to preventable mistakes. Operators might overlook critical testing steps, such as observing the 15-minute wait period to rule out mouth alcohol or giving the subject the right instructions or ensuring the device has been checked for accuracy.
Comprehensive training programs are essential to mitigate these risks. Such programs emphasize not only the technical operations of the devices but also the importance of strict procedural adherence. Trainees learn about the scientific principles underlying the tests, the significance of environmental controls, and the documentation required to uphold the integrity of the process.
Procedural Errors During Sample Collection
Procedural errors are a leading cause of invalid test results, with the majority stemming from operator handling or failure to follow established guidelines. Common mistakes include neglecting to conduct the requisite observation period or failing to replace the mouthpiece for each test subject.
Reusing a mouthpiece risks cross-contamination and introduces variables that compromise the validity of the reading. Proper training and regular auditing of practices can significantly reduce such operator-induced errors. For all DOT testing, a wrapped single use mouthpiece must be used for each test – then discarded after the test.
Regular maintenance and comprehensive operator training, combined with the use of modern breathalyzers, provide the strongest defense against inaccurate data and legal challenges. Advanced technology in modern devices significantly reduces the likelihood of human or procedural errors, enhancing reliability and precision.
While human mishandling is the main cause for errors, the incorporation of these cutting-edge tools ensures organizations can uphold the integrity of their safety and compliance programs. In workplace compliance environments, alcohol testing and drug screening are often managed by the same teams, which is why many organizations source both evidential breath testing supplies and rapid drug test kits from a single provider. Ultimately, utilizing modern breathalyzers protects the public and the individuals subject to these alcohol screening measures, effectively minimizing the potential for errors.