A calibration certificate is a document that records what results a specific breathalyzer showed during calibration. The serial number here is the unique identification number the manufacturer assigns to each device, and it links the test results on the certificate to one actual physical unit. The more devices of the same model an organization runs, or the more it relies on separately attached asset numbers, the less the model name alone can tell you which device a certificate covers.
If the serial number on the certificate differs from the number on the device itself, you need to confirm whether it is a simple typo or whether another device's certificate got mixed in. Until that is confirmed, it is safer not to treat the certificate as evidence that calibration of that device is complete or to use it as material for external submission. The action needed is not to manipulate the device on your own, but to cross-check the physical unit, the intake records, and the certificate against the same number and obtain correction documents from the issuing laboratory.
Why a serial number mismatch is not just a formatting issue
Even if the test results on the certificate look within the normal range, if you cannot link those results to the device they came from, it is hard to explain that device's calibration history. Especially if several units of the same model were sent for calibration at once, you need to distinguish the possibility that one certificate was wrongly matched to another device from the possibility that a single digit was entered incorrectly in the document.
There are also cases where asset numbers and manufacturer serial numbers are confused. An asset number is one the organization attaches for internal management, while the manufacturer's serial number identifies the device itself and its manufacturing records. Which number should appear on the certificate depends on the issuing laboratory's document standards, but you can only judge by comparing the manufacturer serial number shown on the physical unit with the number provided at intake.
So rather than immediately marking it "calibration complete" in the internal equipment list, it is better to set that certificate aside as material whose number is being confirmed. This mismatch alone does not let you conclude that the device's measuring function is faulty or that it needs repair, but the problem of a document not pointing accurately to the device must be resolved separately.
First read and record the number on the physical unit accurately
First, check the model name and serial number on the device's label or at the identification location indicated in the manual. If the label is worn or some characters are blurred by glare, do not guess; photograph the legible part and compare it with the existing equipment list and previous certificates. There is no need to remove the label or disassemble the device in this process.
Next, check the certificate's document number, model name, serial number, and issue date exactly as in the original. If you are viewing a file on screen, you may rename the file for management purposes, but you must not edit the serial number in the PDF or printout yourself. If a user corrects a wrong item in the document, no one can tell who changed it or on what basis.
| What to compare | What to look at | What to do if there is a mismatch |
|---|---|---|
| The device itself | Whether the model name and manufacturer serial number are legible | Take a photo showing the identification location |
| Calibration certificate | Document number, model name, serial number, issue date | Mark the wrong field and the original text as they are |
| Calibration intake records | The number of devices sent and each serial number | Check for omissions or numbers swapped between devices |
| Receipt and storage records | Which device and documents arrived in which package | Check whether another device's certificate got mixed in |
You do not need to have all the records in the table before you can request a correction. However, presenting the intake list as well, rather than sending only the certificate and a photo of the device, gives the issuing laboratory more clues to compare against its work records. That is why, if you sent several devices at once, it is especially important to check the quantity and the order of the numbers together.
Ask the issuing laboratory to confirm the subject, not just to "fix an error"
When you contact the issuing laboratory, it is more accurate to ask it to "confirm which physical unit this certificate's results belong to" than to "change the number." Sending the certificate document number, the serial number on the certificate, the serial number read from the device, and the relevant line of the intake list together makes the scope of the check clear. For the photo, it is better to show one unit with its model name and number legible than to capture several devices at once.
The issuing laboratory can compare intake records with calibration work records to determine whether it is a typo or whether a device and a document were swapped. If another device's certificate was delivered by mistake, what is needed is not a file with only the number changed but material that re-confirms the link between the actual calibrated device and the document. If you have already submitted the certificate to another department or agency, organize the document number of the earlier submission and the scope of the replacement material together so the chain of delivery is not broken.
DATECH's official Downloads center posts product-specific manuals and materials related to calibration requests. A product manual can serve as a reference for confirming a device's model and identification information, but it is not a basis for correcting or approving the serial number on an individual certificate. Changes to a certificate must go through the confirmation procedure of the laboratory that issued it.
The order of checks in a hypothetical case
As a hypothetical example, suppose a safety manager sent 5 breathalyzers of the same model for calibration and received 5 certificates. On one of them, the last digit of the serial number differs from the device, while the intake list shows the same number as the device. The observed fact is that "the device and the intake list match, but only one certificate differs," and at this stage you cannot conclude that it is a simple typo.
Possible interpretations are that a digit was entered incorrectly while the certificate was being prepared, or that the certificate for another device nearby got mixed in. The person in charge can send the issuing laboratory a photo of the device number, the certificate in question, and the relevant row of the intake list, and request a comparison with the work records. Once the issuing laboratory confirms that the calibrated device matched the physical unit and provides a corrected certificate or material that clearly shows the correction, link the currently valid document to that device in the equipment list.
The completion criterion in this case is not just that the number on the certificate now matches the device's number. The device's manufacturer serial number, the calibrated device confirmed by the issuing laboratory, and the current certificate on file must all point to one device, and internal records must show why the earlier document was replaced. Until the check is complete, do not repurpose the certificate in question as material for another device on your own.
How to manage the corrected version alongside the earlier document
When you receive the correction material, check not only the serial number but also the document number, model name, the pages showing the results, and content that shows the reason for correction or the replacement relationship. Rather than deleting the earlier certificate right away, keeping it separate from the version currently in use, marked for example "superseded" or "pending number confirmation," makes it easier to trace which document was submitted in the past. Conversely, if you keep only the corrected version, it may be hard later to explain why the document changed.
You can consider putting the asset number and manufacturer serial number in separate columns in the equipment management list and linking the certificate document number and issue date to them. This reduces the mistake of finding a certificate by asset number alone and linking another device's material. If devices are moved between sites, record on the transfer list not only the device itself but also the document status "certificate number being confirmed," so the receiving side does not mistake it for calibration completion material.
Pair devices one at a time at receipt to prevent recurrence
The key to preventing recurrence is not processing certificates in a batch after receiving them. If you take one device at a time, match the device serial number, the certificate serial number, and the serial number in the intake list in turn, and then move to the next device, you can catch mixed-up deliveries early. If you manage a large number of devices, recording who inspected each one and when in the per-device list lets you narrow down where to check when a mismatch is found later.
A certificate with a mismatched serial number is not a problem to solve by judging the device's accuracy yourself; it is a problem of restoring the link between the document and the physical unit. If you obtain the issuing laboratory's confirmation while preserving the device identification number and intake records, and keep the relationship between the correction material and the earlier material, subsequent equipment management and certificate submission become much clearer.
