When a DOT alcohol test result is reported, employers, employees, and testing professionals all assume the result is accurate. That confidence doesn’t happen by accident. It is built through a system of quality control measures designed to ensure alcohol screening devices (ASDs) and evidential breath alcohol devices (EBTs) function properly and produce reliable results. None-the-less, quality control measures for ASDs are just as important as quality measures instituted for evidential breath alcohol testers (EBTs)
For DOT-regulated employers, quality control is about much more than compliance. It protects the integrity of the testing process, helps prevent inaccurate results, and reduces the risk of regulatory violations. For alcohol testing professionals, quality control provides assurance that every test is administered using devices that meet performance standards and is operating as intended.
Whether a testing program uses breath alcohol screening devices or saliva alcohol screening devices (ASDs), quality control serves the same purpose: building trust in the testing process. However, the quality control requirements for these technologies differ significantly, making it important for employers and testing professionals to understand their responsibilities for each testing method.
Understanding the Difference Between an ASD and an EBT
When discussing quality control in DOT alcohol testing, it’s important to understand the distinction between an Alcohol Screening Device (ASD) and an Evidential Breath Testing (EBT) device. While both are used within the DOT alcohol testing process, they serve different purposes and are subject to different quality-control expectations.
An ASD can be used to collect a breath sample or saliva sample and is only used to perform a DOT screening test to determine whether alcohol may be present. If the screening result is 0.02 or greater, a confirmation test must be conducted using an EBT. The EBT serves as the evidential device and provides the confirmation result used for DOT compliance purposes.
EBT Requirements
The DOT outlines specific requirements for EBTs that ASDs do not meet. Evidential breath testers must be able to conduct an Air Blank prior to the confirmation test. They must also be able to provide a print-out of the alcohol test result. Alcohols Screening Devices are not subject to these same requirements, although some breath alcohol ASDs can perform an Air Blank prior to the screening test result. Not all ASDs can produce a printed result. In this case, the screening test technicians will handwrite the result in Step 3 of the alcohol test form.
Because EBTs are used to produce the official confirmation test result, they are subject to more rigorous requirements than ASDs. However, this does not diminish the importance of quality control for screening devices. In many testing programs, ASDs perform the majority of alcohol tests, making their reliability equally important to maintaining confidence in the testing process.
ASD EBT Comparison Table
| Feature | Alcohol Screening Device (ASD) | Evidential Breath Testing Device (EBT) |
| Primary Purpose | Initial alcohol screening | Screening and Confirmation testing |
| Used For | Initial screening test only | Initial screening test; confirmation test when a screening test result is .020 or greater |
| Test Method | Breath or oral fluid | Breath only |
| DOT Role | Preliminary determination | Evidential determination |
| Quality Assurance Plan (QAP) | Required | Required |
Why Quality Control Matters in DOT Alcohol Testing
The DOT’s alcohol testing program is designed to promote safety in transportation industries where impairment can have serious consequences. The credibility of that program depends on the accuracy and reliability of every alcohol test performed.
Without appropriate quality control measures:
- Devices may produce inaccurate results.
- Testing professionals may unknowingly use defective tools.
- Employers may face compliance violations during audits or investigations.
- Employees may lose confidence in the fairness of the testing process.
- Test results may become more difficult to defend if challenged.
Quality control helps prevent these risks by ensuring that alcohol screening devices operate within established performance standards and that testing procedures are followed consistently. Ultimately, quality control protects everyone involved in the testing process.
Quality Control Is Not the Same as an Accuracy Check
One of the most common misconceptions in workplace alcohol testing is that quality control and accuracy checks are the same thing. They are not.
An accuracy check is a specific procedure performed to verify that a breath alcohol device is producing readings within the manufacturer’s acceptable tolerance range. It is one important component of quality control.
Quality control is the broader system that supports reliable testing results. It includes:
- Accuracy checks
- Quality Assurance Plan (QAP) requirements
- Air blanks when applicable
- Device maintenance procedures
- Proper documentation
- Manufacturer instructions
- Operator training and competency
- Lot verification using quality controls for saliva devices
Think of an accuracy check as one tool within a larger quality-control framework.
A device may successfully pass an accuracy check, but if documentation is incomplete, quality assurance requirements are ignored, or saliva device quality controls are not performed, the overall testing process may still be compromised.
For DOT-regulated employers, understanding this distinction is critical because compliance depends on more than simply verifying that a device appears to be working.
Quality Control Requirements for Alcohol Screening Devices (ASDs)
Alcohol Screening Devices are commonly used during the initial screening stage of DOT alcohol testing. These devices provide a quick determination of whether alcohol may be present at the .020 or greater BrAC level, thus triggering the required confirmation test.
Many ASDs are DOT-approved breathalyzer instruments that measure alcohol concentration, DOT regulations require specific quality-control procedures to ensure their accuracy.
Accuracy Checks Help Verify Device Performance
Monthly accuracy checks are one of the most important quality-control procedures for breath alcohol screening devices. They are also a requirement for breathalyzers that appear on the conforming products list of ASDs.
An accuracy check uses a known alcohol standard to verify that the device is reading within the acceptable range established by the manufacturer and documented in the device’s Quality Assurance Plan.
These checks help answer a simple but critical question: Is the device measuring alcohol accurately?
Without regular accuracy checks, testing personnel may not know whether the device has drifted outside acceptable performance limits.
For employers, maintaining documentation of required accuracy checks demonstrates that the device was functioning properly when tests were conducted. This documentation can become particularly important during compliance audits, investigations, or legal challenges.
Following the Device’s Quality Assurance Plan
Every DOT-approved breath alcohol screening device must have a Quality Assurance Plan, commonly referred to as a QAP. The QAP is developed by the device manufacturer and outlines procedures necessary to ensure the device continues to operate according to approved performance standards.
A QAP typically addresses:
- Accuracy check procedures
- Accuracy check frequency
- Acceptable tolerance limits
- Maintenance requirements
- Corrective actions when a device fails an accuracy check
- Documentation requirements
The QAP is not merely a recommendation. It serves as the manufacturer’s roadmap for maintaining device performance and reliability.
Employers and testing professionals should be familiar with the QAP requirements for every alcohol screening device they use and should maintain records demonstrating compliance with those requirements.
Failure to follow a device’s QAP can create compliance concerns and may undermine confidence in test results.
The Role of Air Blanks in Breath Alcohol Testing
Although it’s not a DOT requirement, many alcohol screening devices perform an air blank before a screening test is administered. An air blank is essentially a check of the device’s fuel cell to ensure no residual alcohol molecules are present before the next test begins. The purpose of the air blank is straightforward: it helps ensure that residual alcohol from a previous test is not present in the device.
If residual alcohol remained in the device after a previous subject’s test, it could potentially influence subsequent readings. By verifying that the fuel cell is clear before another test is administered, the air blank helps support the accuracy and integrity of the testing process.
Although the air blank occurs quickly and often goes unnoticed by the person being tested, it serves an important quality-control function. It is another example of how multiple layers of quality control work together to ensure reliable testing outcomes.
Quality Control for Saliva Alcohol Screening Devices
While breath alcohol screening devices rely on electronic measurements and accuracy checks, saliva alcohol screening devices require a different quality-control approach. This difference is often overlooked.
Many employers are familiar with ASD accuracy checks but may not fully understand the quality-control responsibilities associated with saliva alcohol testing devices.
Because saliva alcohol screening devices are disposable test kits rather than electronic instruments, quality control focuses on verifying the performance of each lot of devices received from the manufacturer.
Why Lot Verification Matters
Even when devices come from a reputable manufacturer, production variations may occur. Lot verification using positive and negative controls helps confirm that devices from a newly received shipment perform as expected before they are used in DOT alcohol testing.
This process provides assurance that the devices are capable of producing accurate and reliable results. Without lot verification procedures, testing personnel may have no way of identifying manufacturing defects or performance issues before testing begins.
Positive and Negative Quality Controls for Saliva Devices
One of the most important quality-control procedures for saliva alcohol screening devices is conducting positive and negative quality checks when a new box or lot is received. These controls help verify that the devices respond appropriately under known conditions.
Positive Quality Controls
A positive quality control uses a known alcohol-positive sample or control material. The purpose is to confirm that the device correctly identifies the presence of alcohol. A successful positive control demonstrates that the device can detect alcohol when alcohol is actually present.
Negative Quality Controls
A negative quality control uses a sample that does not contain alcohol. The purpose is to confirm that the device correctly produces a negative result when alcohol is absent. A successful negative control demonstrates that the device is not generating false positive results.
Why Both Controls Are Necessary
Using both positive and negative controls provides a more complete picture of device performance. Together, they help verify that the test strips in that lot can:
- Detect alcohol when present
- Avoid detecting alcohol when absent
- Perform according to manufacturer specifications
This process creates confidence that the devices are functioning properly before they are used for employee testing. For employers and testing professionals, these quality-control procedures are an important safeguard against inaccurate test results.
Documentation Is a Critical Part of Quality Control
Quality control procedures have limited value if they are not properly documented. Documentation provides evidence that required procedures were performed and that devices were functioning appropriately at the time testing occurred.
Records may include:
- Accuracy check logs
- QAP documentation
- Maintenance records
- Corrective action records
- Lot verification records
- Positive and negative quality-control results
- Device service records
During a DOT audit or compliance review, documentation often becomes the primary means of demonstrating that quality-control requirements were followed. Maintaining organized records can help employers avoid unnecessary compliance concerns and support the defensibility of their testing program.
Common Quality-Control Mistakes
Several quality-control issues appear repeatedly in alcohol testing programs.
Common mistakes include:
- Missing required accuracy checks
- Failing to follow QAP requirements
- Incomplete documentation
- Using devices beyond manufacturer recommendations
- Failing to perform positive and negative controls on new saliva-device lots
- Not documenting corrective actions after quality-control failures
- Assuming quality control is someone else’s responsibility
Each of these issues can weaken confidence in the testing process and increase compliance risk. Fortunately, they are also preventable through proper procedures, training, and oversight.
Building Trust Through Quality Control
At its core, quality control is about trust. Employees trust that testing devices produce accurate results. Employers trust that their testing programs meet DOT requirements. Testing professionals trust that the equipment they use is functioning properly. Regulators trust that the industry’s testing processes support transportation safety. That trust is built through consistent attention to quality-control procedures.
Whether performing required accuracy checks on an alcohol screening device, following a manufacturer’s Quality Assurance Plan, relying on air blanks to prevent contamination, or conducting positive and negative controls on a newly received lot of saliva alcohol screening devices, every quality-control step contributes to the integrity of the testing process.
Quality control is not simply a compliance requirement. It is the foundation that supports accurate results, defensible testing programs, and confidence in DOT alcohol testing from start to finish.