ISO 17025 Calibration: What It Is, Why It Matters, and What to Look for in a Calibration Lab

When you’re choosing a calibration service for healthcare equipment, a certificate alone doesn’t tell you everything you need to know. The more important question is whether the laboratory has the competence, processes and traceability to produce reliable measurement results.

This is where ISO 17025 calibration matters. ISO/IEC 17025 sets requirements for the competence, impartiality and consistent operation of testing and calibration laboratories.

What Is ISO 17025?

The international standard for calibration laboratories

ISO/IEC 17025 is the international standard for testing and calibration laboratories. It covers areas such as technical competence, laboratory processes, equipment, personnel, measurement methods and the reliability of results.

For healthcare facilities, this provides greater confidence that equipment has been calibrated through controlled, technically sound processes.

ISO 17025 vs ISO 9001

The two standards serve different purposes.

ISO 9001 focuses on an organisation’s quality management system. ISO/IEC 17025 goes further for laboratories by addressing their technical competence and ability to produce valid testing and calibration results.

So, having ISO 9001 certification does not automatically mean a company’s calibration service meets ISO/IEC 17025 requirements.

What does ISO 17025 require?

A laboratory must demonstrate competence in the specific calibration activities it performs. This includes suitable equipment, competent personnel, appropriate methods, quality controls, traceability, and processes to ensure valid results.

Why ISO 17025 Accreditation Matters in Healthcare

Traceability to measurement standards

Calibration compares an instrument’s measurements against known standards. Traceability connects those measurements through an unbroken chain of calibrations to recognised references.

SAC has specific requirements for measurement traceability and states that relevant reference equipment should be calibrated through recognised routes, including an SAC-accredited laboratory for the relevant calibration scope.

Competent laboratory personnel

Accreditation also assesses the technical competence of the laboratory and its staff. SAC-SINGLAS evaluates both technical competence and management processes, with assessments carried out by technical experts in the relevant fields.

Data integrity and documentation

A reliable calibration process needs clear records, controlled procedures and results that others can review and trace. This becomes particularly important when healthcare teams manage large equipment inventories or need to demonstrate maintenance and calibration history.

The role of SAC in Singapore

The Singapore Accreditation Council (SAC) is Singapore’s national accreditation body. The SAC-SINGLAS scheme assesses testing and calibration laboratories against ISO/IEC 17025 and relevant technical requirements.

What Makes an ISO 17025 Calibration Certificate Different?

What should a certificate include?

A calibration certificate should clearly identify the equipment tested, the calibration results, relevant standards or methods, and information needed to trace the work back to the laboratory.

If the service is accredited, check that the certificate falls within the laboratory’s accredited scope. SAC accreditation applies only to specific calibration activities, not everything a laboratory offers.

What is measurement uncertainty?

No measurement is perfectly exact. Measurement uncertainty describes the range around a reported result within which the true value is expected to lie.

ISO/IEC 17025 requires laboratories to address measurement uncertainty where applicable. SAC also provides specific guidance on how to evaluate and express it.

How do you verify accreditation?

Don’t rely only on a supplier’s website or a logo on a certificate. Check the laboratory through SAC’s accredited organisation listings and confirm that its scope covers the type of calibration you require.

Questions to Ask When Selecting a Calibration Lab in Singapore

Before appointing a calibration laboratory for a Singapore healthcare team, ask:

• Is the laboratory SAC-accredited to ISO/IEC 17025?
• Does its accreditation scope cover my equipment and measurement type?
• Can it provide on-site calibration, or must equipment be sent to the lab?
• What are the usual turnaround times?
• What support is available if equipment fails calibration or requires repair?

These questions can help you compare laboratories based on technical capability rather than price or turnaround alone.

In-House Calibration vs Accredited Third-Party Services

When is in-house calibration viable?

Larger healthcare organisations may maintain their own calibration capabilities for certain equipment. This can make sense when the team has the right reference standards, facilities, procedures, training and quality controls.

However, having an instrument and a trained technician does not automatically make the work ISO 17025-accredited.

The risk of untraceable calibration

If your reference equipment lacks suitable calibration or traceability, you may not have enough evidence to demonstrate that your results are reliable.

For critical equipment, an accredited external laboratory can provide an independent assessment backed by its defined accreditation scope.

Why use an accredited calibration laboratory?

An external laboratory can also reduce the workload on internal teams while providing documented results and technical expertise. For hospitals with diverse equipment, the right partner can support calibration as part of a wider maintenance and equipment management programme.

Why Leedon’s Calibration Service Matters

At Leedon, we operate an ISO/IEC 17025-accredited Rigel Medical Service Centre in Singapore. We have maintained this accreditation since 2018 and describe the facility as Singapore’s first SAC-accredited medical tester calibration laboratory.

Our service covers calibration, repair and servicing for Rigel Medical biomedical test equipment. We also opened an Approved IMT Calibration Centre in Singapore in 2026 for gas flow devices and analysers.

For healthcare teams, this means you can work with a local technical partner who understands both the equipment being calibrated and the calibration process itself.

Frequently Asked Questions

Does a calibration certificate have to come from an ISO 17025 lab?

Not necessarily. However, if your organisation requires accredited calibration, the laboratory must hold the appropriate accreditation and scope for the calibration performed.

How long is a calibration certificate valid?

There is no universal validity period. The appropriate interval depends on factors such as equipment type, manufacturer recommendations, usage, risk and previous calibration results.

What happens if my equipment fails calibration?

The laboratory should report the results, and your team can assess whether the equipment needs adjustment, repair, further testing or removal from service. You should also consider whether previous measurements may have been affected.