ISO 13485 section 7.6 generates recurring audit findings.
Not because the requirements are obscure. Because they are treated as an administrative task: a calibration schedule is managed, certificates are filed, and the subject is considered closed.
That is not how an auditor reads the clause.
What the auditor looks for is evidence that your measurement system is reliable on a continuous basis, not only on the day of the certificate.
What section 7.6 requires
ISO 13485:2016 requires that measuring equipment whose results influence product conformity be:
- calibrated or verified at specified intervals, against standards traceable to national or international measurement standards;
- identified so that its calibration status can be determined at any time;
- protected against adjustments that could invalidate the results;
- protected against damage and deterioration during handling, maintenance and storage.
One point manufacturers often overlook: when no national or international standard exists for the type of measurement concerned, the reference used must be recorded. This is not an escape route. It is an additional documentation requirement.
Calibration or verification: the distinction that matters
The two terms are not interchangeable. Confusing them in a procedure is a warning signal for an auditor.
Calibration
Calibration establishes the relationship between the value indicated by the instrument and the true value, against traceable standards. It is performed by a COFRAC-accredited laboratory or equivalent. The certificate issued must explicitly state the metrological traceability. Without this statement, the certificate does not comply with section 7.6. This is a finding raised systematically in audits.
Verification
Verification consists in confirming that specified requirements are met. It may be conducted internally, according to a documented procedure, with internal standards that are themselves calibrated. It does not require an accredited laboratory. It does require a procedure, traceable standards, and records.
How to choose between the two
For critical equipment, whose measurements directly determine device conformity, traceable external calibration is expected. For secondary equipment used for indication only, documented internal verification may suffice.
The question to ask for each item of equipment: if this instrument gives an incorrect value, could a nonconforming device be released? If the answer is yes, external calibration is required.
What auditors actually verify
The equipment register
Each item of equipment subject to calibration or verification must be listed in a register: unique identifier, location, calibration frequency, current status. A register without a unique identifier or without a next calibration date is incomplete.
Traceability of certificates
Calibration certificates must state traceability to national or international standards, with reference to the BIPM where applicable. A certificate that does not cite this traceability is not compliant. This point comes up in almost every ISO 13485 section 7.6 audit.
Compliance with intervals
The calibration frequencies defined in your procedure must be respected. Equipment whose calibration is overdue at the time of the audit constitutes a finding. The auditor checks the dates, not only the certificates.
The procedure when equipment is found out of tolerance
This is the question auditors ask almost without fail: what do you do if a piece of equipment is found out of tolerance during calibration?
Section 7.6 requires it explicitly: the organisation must assess and record the validity of previous measurement results. In practical terms:
- Identify the date of the last valid calibration.
- List all products measured or inspected with the faulty equipment since that date.
- Reassess their conformity. Depending on the outcome, corrective actions may be necessary, including the recall of products already delivered.
- Document everything: decision taken, justification, follow-up.
A procedure that only says “send the equipment for repair” is incomplete. It is the retrospective part of the management that makes the difference between a minor finding and a major one.
The three most frequent mistakes
Confusing a calibration certificate with proof of conformity
A certificate attests to a measurement at a given moment. It does not guarantee that the equipment has remained within tolerance since. This is why calibration intervals, defined according to use and observed drift, are as important as the certificates themselves.
Forgetting subcontractor equipment
If a service provider performs critical inspections with its own equipment, its calibration records must be accessible and compliant. Responsibility remains with the manufacturer.
Treating the reassessment as a formality
When equipment is found out of tolerance, the reassessment of previous measurements is not optional. The record of this reassessment, with the conclusions and the actions taken, is required at the next audit.