A breathalyzer is a device that measures the alcohol in a person's breath. Where results are used for work decisions, such as checks before entering a workplace, checks before driving a vehicle, or an agency's management of test records, you need to manage not only the readings but also whether the device was within its set calibration interval. The calibration due date is the date set for the next calibration, based on the product's user manual or the management standard set by the organization.
Finding a device past its due date does not immediately confirm a fault or past measurement errors. What is clear, however, is that the device has not gone through its scheduled verification procedure. So the key is not to hurry to rewrite the date but to take the device out of use on site and keep a continuous record of the facts from its last use to approval for reuse.
Separate it from use on site as soon as you find it
When you notice from the management log or certificate that the due date has passed, first check that the serial number on the device matches the number in the log. This prevents you from making a judgment based on the certificate or due date of another unit of the same model. If the numbers match and the due date really has passed, take the device out of the testing location, charging shelf, or shared storage and move it to a separate storage place.
Quarantine here does not mean disposal or repair. It is a measure to keep a breathalyzer whose usability has not yet been confirmed from getting mixed in with other working devices and used again. Attach a label that shows its status, such as "Do not use until calibration is confirmed," where it does not cover the device information, the screen, or the mouthpiece connection where breath is blown in. Do not disassemble the device or make adjustments to correct its readings.
If the device was in use, notify the person responsible for testing and the person responsible for equipment management on the same day, and decide whether a spare device that has been confirmed ready can be deployed. Even if there is no spare, rather than covering up the problem by continuing to use the overdue device temporarily, it is better to decide separately how testing work will continue, which reduces confusion about status.
Fix the dates and usage history together
After you find that the due date has passed, do not overwrite existing dates or records. To tell later whether it was an actual lapse in management or an incorrect entry of the basis for calculating the due date, the information at the time of discovery must remain. In particular, it is best to record the last use date based on verifiable test records or usage records, not on an "estimate."
If you link at least the following information to the physical label and the management log, as in the table below, people can talk about the same device even when different people handle the calibration request and the internal review.
| What to record | Specific details to write | Why it is used for the next step |
|---|---|---|
| Device identification | Model name, device serial number, storage location at the time of discovery | Identifies the quarantined device without confusing it with other equipment |
| Fact that the due date passed | Calibration due date, date of discovery, basis for the due date | Lets you review whether it is an entry error or an actual lapse |
| Last use information | Confirmed last test date and place of use | Sets the range of past records to examine |
| Condition at the time of discovery | Power indication, screen messages, any visible damage | Lets you describe symptoms accurately when submitting for calibration or repair |
Record separately whether the basis for the due date is the product user manual, the latest certificate, or the organization's internal management standard. If there are signs that the date was entered incorrectly, keep the original entry and the reason for the change, then check the source document again. The mere possibility that the date is wrong is not a reason to resume use on site.
Separate past test records from future use
The fact that the due date has passed is a question of whether the device can continue to be used from now on. Test records already produced are a separate matter to review. You cannot conclude that all earlier results were wrong just because the due date was missed. Conversely, the absence of anything unusual in the later calibration result does not automatically approve all records from the overdue period.
As a hypothetical example, suppose Unit A, used for pre-entry testing, had a due date of June 1, and this was discovered in the management log on June 12. The facts to observe are Unit A's serial number, the last verifiable date of use, the test records from June 1 to the date of discovery, and whether there were any abnormalities on the screen or in appearance at the time. A possible interpretation here is that "the calibration point has passed, but whether there was an actual measurement problem is not yet known."
A possible action is to quarantine Unit A, classify which work decisions the records from that period were used for, and then obtain the calibration result. If any department submitted the test records or used them as the basis for a particular decision, also confirm the handling standard for those records. The completion standard in this case is that, after Unit A has received the result of calibration or any necessary inspection, you review whether it falls within the set acceptance criteria and clearly decide whether it can be reused. Simply having submitted it for calibration or having the device returned does not count as complete.
Pass on the overdue facts as they are in the calibration request
When you contact the calibration body or manufacturer, prepare the model name and serial number, the latest certificate, and the calibration interval standard you have been applying. Also pass on, without leaving anything out, the fact that the due date has passed, the confirmed last date of use, and any symptoms found at the same time, such as power problems, display errors, or damage. This helps determine whether the device needs repair or inspection, separately from whether it needs calibration.
Calibration intervals may differ by product, so do not set dates based on how another model is operated. If the user manual for the model is available on the official Downloads page, checking that manual against the latest certificate makes it easier to confirm the basis for the current due date. Even if you suspect abnormal readings, the appropriate approach is to describe the symptoms in the submission information rather than adjusting the sensor or internal parts on site.
Decide on approval for reuse after reading the results
After calibration or an intermediate check is finished, use the serial number to confirm again that the device named in the result document matches the unit you quarantined. Then review whether the result meets the usage standard the organization set in advance, and if there was any repair, link what was done to the management log. The international guidance document ILAC-G24:2022/OIML D 10:2022 also presents an approach of checking, before approving further use of equipment, whether calibration or intermediate check results fall within limits set in advance.
If it is decided that the device can be reused, remove the quarantine label and record the new calibration due date and the basis for calculating it. Conversely, if the result does not meet the standard or further confirmation is needed, keep the device in quarantine. If you also record who checked the result and who put the device back on site, you reduce the chance that unconfirmed equipment gets mixed back in after a shift change or a change in staff.
