RAS testing for colorectal cancer patients is reliable in European laboratories that pass external quality assessment.

Wild-type status of KRAS and the NRAS gene (exon 2, 3, and 4) in the tumor should be determined before treatment of metastatic colorectal cancer (mCRC) patients with EGFR-targeting agents. There is a large variation in test methods to determine RAS status, and more sensitive detection methods were recently introduced. Data from quality assessment programs indicate substantial error rates. This study assessed the completeness and correctness of RAS testing in European laboratories that successfully passed external quality assessment (EQA). Participants were requested to send material of their most recent ten patients with mCRC who had been tested for RAS status. Isolated DNA, a hematoxylin and eosin stained tissue slide with a marked area for macrodissection and accompanying patient reports were requested. Samples were reevaluated in a reference laboratory by using a next-generation sequencing approach. In total, 31 laboratories sent in the requested material (n = 309). Despite regulations for anti-EGFR therapy, one institute did not perform full RAS testing. Reanalysis was possible for 274 samples with sufficient DNA available. In the hotspot codons of KRAS and NRAS, seven discordant results were obtained in total, five of them leading to a different prediction of anti-EGFR therapy efficacy (2%; n = 274). Results show that oncologists can rely on the quality of laboratories with good performance in EQA. Oncologists need to be aware that the testing laboratory participates successfully in EQA programs. Some EQA providers list the good performing laboratories on their website.

Accreditation of the PGD laboratory.

Accreditation according to an internationally recognized standard is increasingly acknowledged as the single most effective route to comprehensive laboratory quality assurance, and many countries are progressively moving towards compulsory accreditation of medical testing laboratories. The ESHRE PGD Consortium and some regulatory bodies recommend that all PGD laboratories should be accredited or working actively towards accreditation, according to the internationally recognized standard ISO 15189, 'Medical laboratories-Particular requirements for quality and competence'. ISO 15189 requires comprehensive quality assurance. Detailed management and technical requirements are defined in the two major chapters. The management requirements address quality management including the quality policy and manual, document control, non-conformities and corrective actions, continual improvement, auditing, management review, contracts, referrals and resolution of complaints. Technical requirements include personnel competence (both technical and medical), equipment, accommodation and environment, and pre-analytical, analytical and post-analytical processes. Emphasis is placed on the particular requirements of patient care: notably sample identification and traceability, test validation and interpretation and reporting of results. Quality indicators must be developed to monitor contributions to patient care and continual improvement. We discuss the implementation of ISO 15189 with a specific emphasis on the PGD laboratory, highlight elements of particular importance or difficulty and provide suggestions of effective and efficient ways to obtain accreditation. The focus is on the European environment although the principles are globally applicable.

Consensus on the use and interpretation of cystic fibrosis mutation analysis in clinical practice.

It is often challenging for the clinician interested in cystic fibrosis (CF) to interpret molecular genetic results, and to integrate them in the diagnostic process. The limitations of genotyping technology, the choice of mutations to be tested, and the clinical context in which the test is administered can all influence how genetic information is interpreted. This paper describes the conclusions of a consensus conference to address the use and interpretation of CF mutation analysis in clinical settings. Although the diagnosis of CF is usually straightforward, care needs to be exercised in the use and interpretation of genetic tests: genotype information is not the final arbiter of a clinical diagnosis of CF or CF transmembrane conductance regulator (CFTR) protein related disorders. The diagnosis of these conditions is primarily based on the clinical presentation, and is supported by evaluation of CFTR function (sweat testing, nasal potential difference) and genetic analysis. None of these features are sufficient on their own to make a diagnosis of CF or CFTR-related disorders. Broad genotype/phenotype associations are useful in epidemiological studies, but CFTR genotype does not accurately predict individual outcome. The use of CFTR genotype for prediction of prognosis in people with CF at the time of their diagnosis is not recommended. The importance of communication between clinicians and medical genetic laboratories is emphasized. The results of testing and their implications should be reported in a manner understandable to the clinicians caring for CF patients.

Quality control in molecular genetic testing.

DNA-based testing for genetic diseases has developed from nothing into a principal part of laboratory medicine over the past 15 years. In the rush to bring these powerful new technologies into medical use, issues of quality have not always been given sufficient attention. Efforts are now being made to assess the quality of the output of genetic testing laboratories, and the results show that there is room for improvement.

Recommendations for quality improvement in genetic testing for cystic fibrosis. European Concerted Action on Cystic Fibrosis.

These recommendations for quality improvement of cystic fibrosis genetic diagnostic testing provide general guidelines for the molecular genetic testing of cystic fibrosis in patients/individuals. General strategies for testing as well as guidelines for laboratory procedures, internal and external quality assurance, and for reporting the results, including the requirements of minimal services in mutation testing, the nomenclature for describing mutations, procedures to control false-positive amplification reactions and to validate tests, and guidelines to implement a quality system in a molecular diagnostic laboratory are reviewed.

Genetic testing and quality control in diagnostic laboratories.

To evaluate the quality of genetic testing for cystic fibrosis, 136, 145 and 159 laboratories participated in a European study in 1996, 1997 and 1998, respectively. We sent six purified DNA samples carrying the more common CFTR mutations with the request to test them using routine protocols. A panel of experts reviewed the results together with the raw data.

Evaluation of CFTR gene mutation testing methods in 136 diagnostic laboratories: report of a large European external quality assessment.

Within the framework of the European Concerted Action on Cystic Fibrosis (Biomed-2, BMH4-CT96-0462) a quality assessment was set up for 135 European and one Australian laboratory. Six DNA samples were sent to the various laboratories. These samples carried the following CFTR genotypes: dF508/N1303K; dI507/wild; dF508/G551D; dF508/621 + 1 GtoT; R553X/wild and 1717-1 GtoA/wild. Each laboratory was asked to process the samples as they routinely do, whether they checked for all mutations or not. More than 75% of the laboratories screened for at least six of these mutations. Heteroduplex analysis was the most frequently used primary testing method (47%), in many instances followed by restriction enzyme digestion. Only a minority of the laboratories made use of a commercial CFTR mutation detection kit. On average, 91% of the laboratories correctly typed both alleles of a given DNA sample. However, 35% of the laboratories incorrectly typed one or more alleles from a total of 12 alleles included in the trial. One laboratory even failed to identify four of the different alleles correctly. The genotyping error frequency tended to be lower in laboratories which perform more than 200 CFTR mutation analyses per year. The results of this quality control trial suggest that there are many laboratories (35%) which have a percentage of errors unacceptable in a routine testing setting. The development of a consensus testing strategy for routine diagnostic laboratories and centralised mutation analysis facilities for rare or country-specific mutations in a limited number of expert centres, in combination with regular training sessions and quality assessments, should further improve genotyping.