What is accreditation? In the technical world of metrology and testing, the term accreditation represents the highest level of formal recognition a laboratory can achieve. While often confused with “certification,” accreditation is a much more rigorous and specific process.
To understand accreditation deeply, we must look at it through the lens of ISO/IEC 17025, the international gold standard for testing and calibration laboratories.
1. Defining Accreditation: Competence vs. Compliance
The most critical distinction to make is between Certification and Accreditation.
- Certification (e.g., ISO 9001): This is a third-party audit of a company’s management system. It proves that the organization has a documented way of working, handles complaints well, and seeks continuous improvement. However, it does not prove that the measurements they make are accurate.
- Accreditation (e.g., ISO/IEC 17025): This is a formal recognition of technical competence. It proves not only that the laboratory has a quality system, but also that its staff are experts, its equipment is top-tier, and its measurement results are scientifically valid and traceable to international standards.
In short: Certification says, “We have a system.” Accreditation says, “We have a system, and we are technically experts at what we do.”
2. The Pillars of Accreditation (ISO/IEC 17025)
For a laboratory to be accredited, it must undergo a grueling assessment by a National Accreditation Body (such as UKAS in the UK, NVLAP/A2LA in the USA, or TÜRKAK in Turkey). The assessment focuses on five key pillars:
A. Metrological Traceability
Accreditation ensures that every measurement is “traceable.” This means the laboratory can prove its measurements are linked back to the International System of Units (SI) through an unbroken chain of calibrations. Without this, a measurement in one country might not mean the same thing in another.
B. Measurement Uncertainty
An accredited lab never provides just a single number. They provide a value followed by an Uncertainty Statement (e.g., 10.005 mm±0.002 mm). This mathematical calculation accounts for every possible error source, from the operator’s heartbeat to the expansion of metal due to heat.
C. Technical Competence of Personnel
Assessors don’t just look at diplomas; they watch technicians perform the work. They interview staff to ensure they understand the physics behind the measurement and the limitations of the equipment they are using.
D. Equipment and Environment
The lab must prove its equipment is fit for purpose and maintained. Furthermore, the environment (temperature, humidity, vibration) must be strictly controlled and monitored, as these factors can “drift” a measurement away from the truth.
E. Proficiency Testing (PT)
To keep their accreditation, labs must participate in “blind tests” called Proficiency Testing. An independent body sends an unknown sample to multiple labs. If a lab’s result is significantly different from the others, their accreditation can be suspended until they find the error.
3. The Global “Passport”: ILAC and the MRA
One of the most powerful aspects of accreditation is the ILAC Mutual Recognition Arrangement (MRA).
Because accreditation bodies around the world all use the same standard (ISO/IEC 17025) and evaluate each other, they have signed a treaty. This treaty means that a calibration certificate issued by an accredited lab in Germany is legally and technically accepted in Japan, the USA, or Australia.
This eliminates the need for “re-testing” products when they cross borders, saving billions of dollars in global trade. It is the “passport” for technical data.
4. The Value of the “Scope of Accreditation”
Unlike a general business license, accreditation is very specific. A lab is not just “Accredited”; it is accredited for a specific Scope.
For example, a lab might be accredited to calibrate digital thermometers from −50°C to +200°C. If they try to calibrate a thermometer at 500°C, that specific measurement is not accredited. Users must always check the “Annex” or “Scope” document to see exactly what the lab is authorized to do.
5. Summary of Benefits
| For the Laboratory | For the Customer | For the Industry |
| Global recognition of expertise | Reduced risk of faulty data | Standardized global measurements |
| Continuous improvement culture | Legal protection in disputes | Enhanced public safety |
| Competitive marketing edge | Assurance of “Traceable” results | Facilitation of international trade |
What is accreditation?
