Medical laboratory testing

How can we trust the results?

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Never have we been more acutely aware of the importance of reliability when it comes to laboratory testing. As the ongoing COVID-19 pandemic has highlighted, the development of accurate diagnostic tests plays an important role in outbreak management.

Whether a laboratory develops its own test methods or incorporates ones that already exist, there is a lot to be considered and the task bequeathed to them is great. Apart from the general risks of contamination, inadequate equipment or failings in processes that must be rigorously managed, the procedures and tools required for each test can potentially differ.

Since the beginning of the pandemic, ISO has been collaborating with experts in many fields to establish where standards can really make a difference. As a result, experts on ISO’s technical committee for laboratory testing and in vitro diagnostic (IVD) test systems are currently working on international best-practice guidelines to assist laboratories.

The future technical specification ISO/TS 5798, Quality practice for detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by nucleic acid amplification methods, will detail considerations for the design, development, verification, validation and implementation of analytical tests for detecting SARS-CoV-2 using nucleic acid amplification methods. It will include pre-examination and examination process steps for respiratory tract specimens as well as their relevant parameters.

The new technical specification intends to help medical laboratories make the best use of commercially available IVDs when testing for COVID-19 and develop their own tests, so that testing is more reliable and accurate. But consistency and accuracy of results are not just about the type of test used, they are also linked to the overall quality of the laboratory that undertakes the work. Having an internationally agreed level of competence means that results can be trusted. They can then be shared and compared with counterparts overseas, which is an essential step to assure quality control in medical laboratory testing – for COVID-19 as well as any future pandemic.

So how do laboratories demonstrate their competence in a way that is irrefutable?

Let’s start with conformity

One such way is through a system of conformity assessment. Being accredited to a recognized International Standard is a way that laboratories can show they are competent.

ISO/IEC 17025General requirements for the competence of testing and calibration laboratories, is the international reference for laboratories carrying out calibration and testing activities around the world. Developed in conjunction with the International Electrotechnical Commission (IEC), it allows laboratories to implement a sound quality system and demonstrate that they are technically competent and capable of producing valid and reliable results.

ISO/IEC 17025 also helps facilitate cooperation between laboratories and other bodies by generating wider acceptance of results between countries. Test reports and certificates can be accepted from one country to another without the need for further testing, which, in turn, improves international trade.

Conformity assessment is the collective term for the processes that show a product or service meets the requirements of something, such as a standard. It not only gives the product or service the necessary “papers” to demonstrate it conforms, it gives consumers and regulators confidence that certain regulations are met.

The organizations that carry out conformity assessment procedures are known as conformity assessment bodies (CABs). Laboratories, including those performing tests for medical purposes, can be considered to be a type of CAB.

Validating the validator

The next step, called accreditation, is the independent evaluation of CABs against recognized standards to ensure their results are credible and trusted. That way, medical laboratories can demonstrate that they meet the requirements of those standards by getting an independent assessment from what is known as an “accreditation body”.

Accreditation bodies that have been evaluated by their peers as competent can sign arrangements amongst themselves, which in turn increases the acceptance of products and services that are traded internationally.

This process is managed by the International Laboratory Accreditation Cooperation (ILAC) when it comes to laboratory and inspection accreditation.

Counting on confidence

There are a number of standards for  the accreditation of CABs, developed by ISO’s committee on conformity assessment (CASCO). Many of these are published jointly by ISO and its standardization partner, the International Electrotechnical Commission (IEC). Together, these standards make up the “CASCO Toolbox”, which is developed with stakeholders from all over the world and includes the contribution of ILAC, a key ISO partner.

Among its many standards, the CASCO Toolbox includes ISO/IEC 17020Conformity assessment – Requirements for the operation of various types of bodies performing inspection, the ISO/IEC 17021 seriesConformity assessment – Requirements for bodies providing audit and certification of management systems, and ISO/IEC 17065Conformity assessment – Requirements for bodies certifying products, processes and services.

An accreditation body can also be peer-evaluated against ISO/IEC 17011Conformity assessment – Requirements for accreditation bodies accrediting conformity assessment bodies, providing another layer of credibility.

At a time when the accuracy of tests for diseases such as COVID-19 is proving less than perfect, ensuring that laboratories have the highest level of competence is more important than ever. The lengths the industry goes to, with this multi-layered system of international validation, is extremely reassuring as it can help to establish agreed levels of competence and instill trust and confidence in their results. A rare source of comfort in such uncertain times, and one that will prepare us for any new pathogens.

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