Molecular/Genomic reference standards are a class of ‘controls’ or standards used to check the performance of molecular diagnostic assays. Molecular/Genomic Reference Materials (RMs) are selected or engineered to model a specific genetic biomarker as it occurs in a patient

biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a diseas ...

. Reference materials (RM) are used for a calibration of the measuring system, for assessment of a measurement procedure, for assigning values to materials, or for

quality control Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "a part of quality management focused on fulfilling quality requirements". This approach places ...

Molecular reference materials

Molecular reference standards are available in a variety of formats, each of which has strengths and weaknesses. These materials range from synthetic DNA oligonucleotides or patient-derived genomic DNA, to actual patient tissue biopsies with known

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...

status. {, class="wikitable" , - ! Reference Material !! Benefit !! Drawback , - , Recombinant

plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; how ...

s or synthesized oligonucleotides , , Cheap and easy to synthesize. Can control for multiple

allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...

s in a single reaction , , Do not resemble complexity of the whole

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

. Risk of false positives , - , Cell Line Genomic DNA (gDNA), , Mimics complexity of the whole genome , , Can only control for one or a few alleles/

genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...

s or targets at a time. , - , Cell Line Mixtures , , Mimics complexity of the whole genome. Can control for multiple alleles in a single reactions , , Does not mimic the ‘ isogenic’ or similar genetic background between different cells in a tumour. , - , Genetically modified cell line gDNA , , Mimics complexity of the whole genome. Ability to dilute modified gDNA with unmodified gDNA , , Can only control for one or a few alleles/genotypes or targets at a time , - , Genetically modified cell line mixtures, , Mimics complexity of the whole genome. Ability to dilute modified gDNA with unmodified gDNA. Mimics the ‘isogenic’ background of tumour cells , , ---- , - , Patient biopsy samples, , Completely representative, , Not a sustainable source

Proficiency schemes

Proficiency schemes involve the distribution of blinded reference materials to subscription laboratories, and the subsequent scoring and assessment of the proficiency of those labs in their molecular diagnostic testing. Proficiency schemes are usually organized by not-for-profit organizations, usually government affiliated, to which hundreds of laboratories may subscribe. These schemes are funded with the

subscription The subscription business model is a business model in which a customer must pay a recurring price at regular intervals for access to a product or service. The model was pioneered by publishers of books and periodicals in the 17th century, and ...

fees paid by each member laboratory. Proficiency schemes have historically relied upon patient biopsies with known mutation status for distribution to member laboratories. However, due to the significant rise in the number of labs performing molecular testing (in turn caused by the increase in the number of available targeted drugs whose prescription is linked to the presence or absence of a particular biomarker), patient samples are becoming an unsustainable source of reference material. Increasingly, proficiency scheme organizers are turning to genetically modified cell lines as a sustainable and well defined source of reference material. Some of the largest proficiency scheme organizers in the world include:
College of American Pathologists
(CAP) – USA
European Molecular Quality Network
(EMQN) – UK, Europe, EMEA
United Kingdom National External Quality Assessment Scheme
(NEQAS) – UK, Europe, EMEA

Sources

Sources of Certified Reference Materials (CRM) include:
Institute for Reference Materials and Measurements

NIBSC

NIST

Horizon Discovery Reference Standards

Maine Molecular Quality Controls

Molecular ControlsSeracare Life Sciences

World Health Organization - International Reference Materials
More Information can be found on th
CDC
an
Eurogentest
webpages. Cell Line Repositories
American Type Culture Collection (ATCC)

Coriell Cell Repositories

German Collection of Microorganisms and Cell Cultures

Health Protection Agency Culture Collections

Japanese Collection of Research Bioresources

Riken Bioresource Center
Medical tests