Image Source: Unsplash – A person using a calculator on a machine
Calibration records tend to be overlooked until an inspection is close.
That is usually when teams realise the real issue is not whether a device was calibrated once, but whether the company can prove ongoing control. In Singapore, that matters for both GDP and GDPMDS environments because inspectors want evidence that critical equipment is properly managed, documented, and reviewed in a way that supports product quality and regulatory compliance (Health Sciences Authority [HSA], 2023a, 2023b; Pharmaceutical Inspection Co-operation Scheme [PIC/S], 2014).
A clean calibration file does more than satisfy a checkbox. It helps show that your warehouse, transport process, cold chain logistics setup, and monitoring systems are working within control, and that the people managing them understand what to do when something goes wrong (HSA, 2023a, 2023b; PIC/S, 2014).
What Inspectors Typically Expect From Calibration Records?
Inspectors usually start with simple questions.
- What is the equipment?
- Where is it used?
- When was it calibrated?
- What standard was used?
- Was the result acceptable?
- Who reviewed it?
If the answers are scattered across folders, emails, vendor attachments, and memory, the record system is not really inspection-ready. PIC/S says calibration of equipment should be traceable to a national or international measurement standard, and equipment repair, maintenance, and calibration services should be carried out in a way that does not affect product quality. The guide also states that adequate records of repair, maintenance, and calibration activities for key equipment should be kept (PIC/S, 2014).
Singapore’s HSA guidance says measuring equipment used to monitor storage conditions should be calibrated for the required operating range at defined intervals, that calibration should be traceable to national or international standards, and that calibration records should be maintained. For GDPMDS cold-chain settings, HSA also says certificates of calibration should be traceable to national or international standards and should be reviewed and maintained (HSA, 2023a, 2023b).
That is the real expectation: not just proof that calibration happened, but proof that the system around it is controlled.
Essential Fields In A Calibration Certificate Or Equipment Log
A useful record should let someone unfamiliar with the equipment understand its status without guessing.
In practice, an internal equipment log should usually include:
- equipment ID
- description
- model
- serial number
- location
- operating range
- calibration frequency
- last calibration date
- next due date
- service provider
- status
- reviewer
- any linked deviation or Corrective and Preventive Action (CAPA) reference, where issues have been identified and require follow-up
The supporting calibration certificate should usually include:
- the date performed
- method or standard used
- measurement results
- acceptance criteria or tolerance
- pass/fail conclusion
- traceability details for the standards used
That structure is not copied from a single clause. Still, it reflects the documentation, traceability, and review expectations described in GDP, GDPMDS, and ISO/IEC 17025 (International Organisation for Standardisation [ISO], 2017; HSA, 2023a, 2023b; PIC/S, 2014).
This matters across more than just lab instruments
- PIC/S identifies key equipment that may include cold stores, refrigerators, thermo-hygrometers, temperature and humidity recording devices, air handling units, alarm systems, and other equipment used to control or monitor distribution conditions.
- HSA’s GDPMDS guidance for cold-chain medical devices similarly points to monitoring and recording instruments, cold rooms, refrigerators, air handling units, and alarm systems as equipment requiring documented control (PIC/S, 2014; HSA, 2023b).
A common weakness is poor linkage between the paper or PDF certificate and the actual asset on site. If the serial number, asset ID, or location does not clearly match, the record can look complete while still failing the audit test.
How Traceability And Accredited Laboratories Support Audit Confidence
Traceability is not just technical wording. It is what makes a calibration result defensible.
PIC/S states that calibration should be traceable to a national or international measurement standard. HSA’s GDP and GDPMDS guidance repeats the same principle for relevant measuring and monitoring equipment (HSA, 2023a, 2023b; PIC/S, 2014).
ISO/IEC 17025 helps explain why this matters. ISO describes ISO/IEC 17025 as the international standard for testing and calibration laboratories and says it sets requirements for competence, impartiality, and consistent operation, helping ensure accurate and reliable results (ISO, 2017).
That is also why accredited laboratories strengthen audit confidence. Singapore’s Accreditation Council says SAC-accredited laboratories are assessed against international technical and management system standards, including ISO/IEC 17025, under its laboratory accreditation services framework (Singapore Accreditation Council [SAC], 2024).
Using an accredited laboratory does not replace internal review, of course. Your team still needs to confirm that the provider’s scope fits the parameter, range, and type of equipment involved. But when the calibration is performed by a competent, accredited lab with clear traceability, the record is easier to defend during an inspection (ISO, 2017; SAC, 2024).
Managing Due Dates, Out-Of-Tolerance Findings, and CAPA Follow-Up
A calibration system is only reliable if it works before something becomes overdue.
PIC/S says calibration should take place at defined intervals based on risk and reliability, and HSA’s GDPMDS guidance says calibration frequency should be determined based on risk assessment. For temperature monitoring and recording instruments in cold-chain medical device distribution, HSA adds that a minimum three-point calibration covering the operating range and carried out annually is preferred (HSA, 2023b; PIC/S, 2014).
That means due dates should be managed through a controlled register or validated system, not left to stickers on devices or reminders in someone’s inbox.
Out-of-tolerance results need more than a quick fix.
If the equipment fails calibration, the question is not only whether it should be repaired or replaced. The more important question is whether previous readings, storage conditions, or product decisions can still be relied on.
PIC/S states that deviations should be documented and that appropriate corrective and preventive action (CAPA) should be taken where necessary (PIC/S, 2014). In practice, CAPA refers to the structured process used to investigate the issue, identify the root cause, implement corrective action, and prevent recurrence.
A typical follow-up should include:
- containment of the affected equipment
- assessment of potential product or data impact
- root-cause investigation
- clearly documented corrective and preventive actions
For cold-chain environments, HSA guidance also requires that temperature excursions be investigated and their impact on product quality assessed (HSA, 2023b).
Where electronic systems are involved, data integrity becomes part of the same control framework. PIC/S guidance on data integrity states that records should remain attributable, legible, contemporaneous, original, accurate, complete, consistent, enduring, and available throughout the data lifecycle (PIC/S, 2021).
Building A Documentation Workflow That Supports GDP, GDPMDS, And Internal QA
The best workflow is usually the least dramatic one.
- Start with an equipment master list covering every critical asset that affects storage, monitoring, handling, transport, or security.
- Assign ownership.
- Define calibration intervals, reviewer responsibilities, acceptance criteria, escalation triggers, and document retention rules.
PIC/S says documentation should be readily available or retrievable, approved, signed and dated by designated persons, and retained for the required period. It also says records should be made at the time each operation is undertaken (PIC/S, 2014).
Next, connect the documents.
- The equipment register should link to the certificate.
- The certificate should link to maintenance history.
- Any failure should link to a deviation and CAPA record.
For electronic systems, HSA’s GDP guidance says only authorised persons should be able to enter or modify data and that an audit trail should be available for changes and deletions (HSA, 2023a).
Finally, review records on a routine schedule, not only when an inspection is announced. Regular review helps catch overdue items, repeated failures, weak vendors, and gaps in follow-up before they become inspection findings. That is what makes a calibration record system feel audit-ready: not the file itself, but the control behind it (HSA, 2023a, 2023b; PIC/S, 2014).
FAQs
Q. What should be included in a calibration record?
A. A good record usually includes equipment ID, calibration date, due date, standard used, result, tolerance, status, and reviewer approval, plus traceability details where relevant. This is a best-practice synthesis supported by accreditation and GDP expectations.
Q. Does calibration need to be traceable to recognised standards?
A. Yes. Traceability is a core principle in competent calibration systems and supports confidence in measurement accuracy.
Q. Should calibration be done by an accredited laboratory?
A. Using an accredited calibration laboratory strengthens technical confidence and audit defensibility, especially for critical instruments and regulated environments.
Q. What happens if equipment is found out of tolerance?
A. Companies should assess product impact, investigate root cause, document corrective action, and determine whether affected records, batches, or monitoring data need review. This is an operational compliance inference aligned with GDP quality-system expectations and data-integrity principles.
Q. Why are calibration records important during Singapore inspections?
A. Because inspectors assess whether critical equipment is controlled, maintained, and documented in a way that supports product quality and regulatory compliance.
References
Health Sciences Authority. (2023a). Guidance notes on good distribution practice..
https://www.hsa.gov.sg/docs/default-source/hprg-ald/guide-mqa-013.pdf?sfvrsn=3f0805b3_8
Health Sciences Authority. (2023b). GN-33 guidance on the application of Singapore standard GDPMDS. . https://www.hsa.gov.sg/docs/default-source/hprg-mdb/guidance-documents-for-medical-devices/gn-33-r2-guidance-on-the-application-of-singapore-standard-gdpmds-%282023-sep%29-pub.pdf?sfvrsn=d6a33416_2
International Organization for Standardization. (2017). ISO/IEC 17025:2017 – General requirements for the competence of testing and calibration laboratories. .
https://www.iso.org/standard/66912.html
Pharmaceutical Inspection Co-operation Scheme. (2014). Guide to good distribution practice for medicinal products (PE 011-1)..
https://picscheme.org/docview/3450
Pharmaceutical Inspection Co-operation Scheme. (2021). Good Practices for Data Management and Integrity in Regulated GMP/GDP Environments..
https://picscheme.org/docview/4234
Singapore Accreditation Council. (2024). Laboratories..
https://www.sac-accreditation.gov.sg/services/accreditation-services/laboratories/