What kind of calibration should I choose?

23.08.2018 – JKO

When choosing the right calibration for your monitoring equipment, data loggers or manual equipment, it is important to remember that calibration is an inherent part of ensuring that the equipment measures correctly.  Furthermore, it is important that the calibration is traceable to an international standard.

The question is though how to choose the right calibration level as well as determining how this will affect the quality documentation?

Why calibrate?

Almost all requirements from government or customers (GDP, GMP, GLP or other) will focus on that you calibrate your equipment on a yearly basis or based on a risk assessment.

Furthermore, the calibration ensures that the equipment measures correctly. Measurements taken with non-calibrated devices can inherently not be trusted, and thus calibration is a crucial part of all quality work.

Should I buy a service with included calibration and should it be accredited?

When buying monitoring equipment, there are typically 3 varieties to choose from:

  • Uncalibrated devices
  • Traceable calibrated devices
  • Accredited calibrated devices

Below is a short description of the difference between the different types:


Equipment which have not been through a calibration process before being shipped to the customer. There might exist some validation of the product, but this does not guarantee that it measures correctly. No documentation exists on this neither.

Traceable calibration

A traceable calibration is performed using a supplier’s internal procedure, which is validated internally at the supplier’s organisation.

The traceability comes from the reference that the suppliers use, which should be traceable to international standards.

Preferable the supplier uses a reference that is traceable to an accredited laboratory. The supplier should be able to provide information on of traceability as well as documentation.

Accredited calibration

An accredited calibration follows a method and procedure for calibration that has been approved by the national accreditation institute in the country of the supplier. Furthermore it follows the standards of the ISO 17025 standard, which have also been approved by the accreditation body. In other words, the national accreditation body has audited the supplier, ensured that the laboratory overall has high standards and that it follows all standards of calibration to a high level.

What does the calibration level mean for the quality work?

When complying with any quality standard, whether required by law or by your customers, it is paramount that the equipment is qualified and validated for the purpose. This often means that the equipment needs to be calibrated.

If equipment is purchased without calibration, it needs to be ensured that some kind of calibration is performed either internally or externally and that it is possible to obtain documentation of the calibration.

If you opt for traceable calibration, you need to assess whether or not it is sufficient for the purpose. This can include a general risk assessment, affirmation with auditors, risk assessment of the supplier and so on.

The quality manager at your organisation needs to make sure that the calibration that has been performed as well as the documentation, complies with the standards expected from the auditors.

Furthermore, it might be required that the traceability chain is documented, and that a validation of the supplier has been performed, all depending on the requirements from the auditor or the standard you follow.

The easiest way to ensure compliance is to use accredited calibration. In this case,  the tasks associated with risk assessment of the supplier and traceability of the calibration have already been performed by the accreditation body.

When a laboratory is accredited, extensive and continuous auditing of the laboratory is performed to ensure that all methods and procedures live up to a high standard, and that all calibrations are performed in accordance with strict requirements for traceability and quality.