BRAF testing quality control

Detecting, reducing and correcting deficiencies in the testing process

The result of the BRAF mutation test, as in other companion diagnostic tests in the field of personalised/precision medicine, is a key component when selecting the best therapy and making management decisions for patients. Therefore, it is essential that the analysis is consistent and highly reliable, delivering correct results to clinicians, thus there is a need for standardised quality control and assurance.^1,2 This is achieved by implementation of checks designed to detect, reduce and correct deficiencies in a laboratory's internal analytical process prior to the release of patient results.^1,2

US Federal Quality Standards

In the USA, all laboratories that perform testing on human samples for the purpose of providing information for the diagnosis, prevention, or treatment of disease, or for health assessment, must comply with standards set out in the Clinical Laboratory Improvement Amendments (CLIA) programme.³ All such laboratories must apply for certification by the state, and by the Center for Medicare and Medicaid Services (CMS), and comply with the CLIA regulations, before they can accept samples for testing.^3,4 Part of the compliance procedures requires laboratories to establish and follow an internal quality assurance (QA) programme that continually monitors and evaluates the quality of the overall testing process.⁴ The QA programme must:

• Assess the effectiveness of the lab’s policies and procedures
• Identify and correct problems
• Assure the accurate, reliable, and prompt reporting of test results
• Assure the adequacy and competency of the staff

In addition, if problems are identified the lab must initiate corrective action, and document all QA activities. (AAFP)

External Quality Assessment (EQA) and Proficiency Testing (PT) programmes:^1,2,5

• Programmes organised by professional companies/associations or bodies, EQA schemes or PT organisers
• Multiple samples (from real tissue or cell lines), with known mutation status determined by panel of experts and blinded, are periodically sent to participating laboratories for analysis. (Some schemes do this once per year sending multiple samples, some 2–3 times per year)
• Laboratories run the test as they would do with any routine clinical sample and send back a report with the result
• The results from each laboratory are evaluated and rated based on correctness of the result and quality of the report
• Laboratories are then informed and given feedback and often, in case of failure, are consulted and provided with guidance to improve their performance

It is generally accepted that all laboratories performing molecular tests for cancer patients, such as a BRAF mutation test, should be part of an EQA scheme.⁶ There are several available in many countries, some of them providing the service to laboratories from across the globe, such as:

• CAP (College of American Pathologists)
• UK National External Quality Assurance Scheme (NEQAS)

Internal quality control

• In-house procedures for continuous monitoring of operations and systematic day-to-day checking of the produced data to decide whether these are reliable enough to be released⁶
• Performed using ‘control samples’, which undergo the same test procedure along with the tested sample.⁶ It takes place at ‘batch level’, where one particular control sample is analysed together with several patient samples done at once in one run
  • Positive control sample
  • Negative control sample
  • Border-line control sample
• These controls can be prepared by the laboratory or purchased, and can be part of a commercial kit⁶