Multiallelic synthetic quality control material: lessons learned from the cystic fibrosis external quality assessment scheme.

AIM: With the arrival of increasingly complex molecular tests, we are obliged to create new ways to monitor and troubleshoot the underperformance of these multiplex assays. A synthetic multiallelic quality control material has been designed to augment genomic DNA controls. We aimed to evaluate the control on a large scale, testing it on a wide variety of oligonucleotide ligation assays, test protocols, and analysis software. In addition, we investigated how laboratories treat untried and complex materials. METHODS: The synthetic control monitored 32 cystic fibrosis transmembrane conductance regulator mutations and polymorphisms simultaneously. Participants of a cystic fibrosis external quality assessment scheme were invited to analyze the quality control. RESULTS: In total, 58 laboratories participated in this study. Twenty-seven (47%) laboratories detected 32 variants; another 27 laboratories (47%) detected from 31 to 4 variants and 4 participants reported no variants (6%). The main observations included administrative errors when indicating variants on a checklist, errors caused by misreading the instructions for use of the control or assay, and technical problems related to the assay used. CONCLUSION: Synthetic quality control materials proved to be valuable in troubleshooting underperforming assays and complement existing genomic controls. The study also revealed a strong need for increased quality control in the postanalytical phase of testing.

Design, development, validation, and use of synthetic nucleic acid controls for diagnostic purposes and application to cystic fibrosis testing.

We have designed, tested, and validated synthetic DNA molecules that may be used as reference standard controls in the simultaneous detection of mutations in one or more genes. These controls consist of a mixture of oligonucleotides (100 to 120 bases long) each designed for the detection of one or more disease-causing mutation(s), depending on the proximity of the mutations to one another. Each control molecule is identical to 80 to 100 bases that span the targeted mutations. In addition, each oligonucleotide is tagged at the 5' and 3' ends with distinct nucleic acid sequences that allow for the design of complementary primers for polymerase chain reaction amplification. We designed the tags to amplify control molecules comprising 32 CFTR mutations, including the American College of Medical Genetics minimum carrier screening panel of 23, with one pair of primers in a single tube. We tested the performance of these controls on many platforms including the Applied Biosystems/Celera oligonucleotide ligation assay and the Tm Bioscience Tag-It platforms. All 32 mutations were detected consistently. This simple methodology allows for maximum flexibility and rapid implementation. It has not escaped our notice that the design of these molecules makes possible the production of similar controls for virtually any mutation or sequence of interest.