When you collect breathalyzer results from several devices or systems, it is easy to think the data will fall into one set if you just convert the numbers on screen into the same format. However, %BAC and mg/L are not just symbols after a number; they also tell you what the result was displayed to represent. %BAC is a unit used for blood alcohol concentration notation, and mg/L is a unit used for the alcohol concentration in exhaled breath.
A breathalyzer is a device that analyzes a sample of a person's exhaled breath. Test results can be moved from the device screen to stored memory, a smartphone app, or a safety management system, and if the unit or device information is lost along the way, it becomes hard to confirm what even the same number means. So before merging %BAC and mg/L data, what you need to check is not just the unit symbol but in what unit and manner each device displayed and stored its breath analysis result.
Look at the breath sample and the display unit separately
What the device actually receives during a test is not blood but a breath sample. The screen may display breath concentration in mg/L, or it may display it in a blood alcohol concentration format such as %BAC or ‰. So even if a data column is titled %BAC, you must not record it as the result of drawing and analyzing blood directly.
DATECH's official product information for the AF-40BT presents the display ranges separately as 0.000~0.500 %BAC, 0.00~5.00 ‰, and 0.00~2.50 mg/L. It also states the accuracy conditions separately at 0.100 %BAC, 25 ℃, 1.00 ‰, 25 ℃, and 0.50 mg/L, 25 ℃. This information shows that the model supports several display units, but it is not grounds for converting results from other devices by the same rule.
Original information to keep with the number
If only one number and a unified unit remain in the integrated data, you cannot later review where that value came from. You need to keep, together, the number and unit symbol from the original screen or original file, the manufacturer and model name, and the test time. If the display unit can be changed on the device, it is better to record the unit actually shown on screen at the time of the test as a separate field.
| Category | What to keep with it | What to judge before merging |
|---|---|---|
| Original test result | Displayed number, display unit, test time | What value and symbol did the device actually output? |
| Device information | Manufacturer, model name, test mode | Are these results from the same device and the same display method? |
| Meaning of the value | Whether it is a breath analysis value or a breath result shown in another format | Are the subject the number refers to and the display method the same? |
| Converted copy | Converted number, target unit, applicable document, and processing time | Was it created separately on an approved basis while keeping the original? |
For example, if you simply move 0.24 mg/L from an original file into a %BAC column, it can look as though not only the number but also the description of the value has changed. Conversely, a 0.050 shown in %BAC is also hard to trace to a specific device and screen value if the model name and the display setting at the time are missing. This is why you keep converted values in a separate column or a separate dataset without overwriting the original values.
Check the basis for applying a conversion before the formula
The fact that one device displays %BAC, ‰, and mg/L does not mean you can apply a conversion factor found elsewhere to every record in your organization at once. The relationship between display units and the rounding method must be confirmed in the manufacturer's documents for that model or in a technical document approved internally. You should also avoid taking the description of one model and applying it to another model of the same brand or to another manufacturer's device.
As a hypothetical example, suppose mg/L records from device A and %BAC records from device B have both come into a safety management system. The appropriate order is to first confirm the original unit, model name, and test time, then compare how each device displays its breath analysis results, and then check whether there is a conversion document that applies to both devices.
If a document is confirmed, you can keep the original records as they are, create converted copies using the method in the document, and record the applicable document and processing time. If there is no document, or it applies to only one model, present the two units separately. The completion criterion in this case is not putting every value in one column, but deciding whether to compare or keep them separately while each value stays linked to its original unit, device, and conversion basis.
Do not delete results you could not convert
The lack of a conversion basis does not mean you need to delete test results or treat them as blank. If you split mg/L results and %BAC results into separate sections in reports and do not average them together or compare their maximums directly, the original information is preserved. If you record in the data processing log why they were excluded from integrated calculations, you will also know which results to review again once you obtain the documents.
The AF-40BT offers Bluetooth smartphone pairing and storage of 10,000 test results. When results from such a device move to an app or another system, you need to compare not only the transmitted number but also the unit shown on the app screen, the device screen, and any downloaded report. If the device screen shows a unit but the integrated data has none, or it is renamed under a different heading, the number may remain while the meaning of the test result weakens.
Set the scope of comparison according to the purpose of integration
If the purpose is to keep a test history for each device, keeping the original unit and device information may be enough. On the other hand, to build trends over time or a single statistical indicator, you need to confirm, in addition to whether conversion is possible, that the values refer to the same measurement subject and have the same meaning. If you put values with different meanings into the same average or ranking, the calculation is possible but the interpretation is hard to trust.
This work must also be kept separate from judging whether an individual can drive, or when they can drive, from the numbers. The scope of data integration is consistent management of the source, unit, and display method of test results. The first thing to check before merging %BAC and mg/L is not the convenience of conversion but what each device displayed and recorded as the analysis result of the breath sample.
