Ratio primary reference measurement procedure (RPRMP) for the certification of chromium content in biological reference materials

Abstract Primary reference measurement procedure for Cr determination in biological samples by radiochemical neutron activation analysis (RNAA) has been elaborated. The procedure is based on quantitative and selective separation of chromium from neutron irradiated sample by column chromatography using MnO2-Resin and determination of 51Cr by γ-ray spectrometry. Quality components have been incorporated into the RNAA method which makes it possible to meet the requirements of the definition of ratio primary reference measurement procedure. The usefulness of the elaborated procedure to assign the certified values for Cr in new certified reference material (CRMs) based on animal tissues is demonstrated. The tentative certified values for Cr have been proposed for: MODAS M-4 Cormorant Tissue and M-5 Cod Tissue CRMs.

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Ratio primary reference measurement procedure (RPRMP) for the determination of iron in biological materials by RNAA

Radiochimica Acta ◽

10.1524/ract.2012.1927 ◽

2012 ◽

Vol 100 (6) ◽

Cited By ~ 4

Author(s):

R. S. Dybczynski ◽

B. Danko ◽

M. Pyszynska ◽

H. Polkowska-Motrenko

Keyword(s):

Biological Materials ◽

Measurement Procedure ◽

Reference Measurement ◽

Reference Measurement Procedure ◽

Primary Reference

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Reference measurement procedures for the accurate determination of cell concentrations: present status and future developments/Referenzmessverfahren für die genaue Bestimmung von Zellkonzentrationen: Status und zukünftige Entwicklungen

LaboratoriumsMedizin ◽

10.1515/jlm-2011-0008 ◽

2012 ◽

Vol 36 (1) ◽

Cited By ~ 3

Author(s):

Martin Kammel ◽

Andreas Kummrow ◽

Jörg Neukammer

Keyword(s):

Accurate Determination ◽

Measurement Procedure ◽

Cell Counting ◽

Complete Analysis ◽

Reference Measurement ◽

Future Developments ◽

Reference Measurement Procedure ◽

Primary Reference ◽

Cell Concentrations

AbstractAccurate determination of cell concentrations serves as a valuable tool to support medical diagnosis and therapy control, e.g., in haematology, immunology and transfusion medicine. Intra- and inter-laboratory comparability of measurement results is essential for patient safety. To derive the so-called “conventional quantity value” of a measurand as target value for intra- or inter-laboratory quality assurance and to establish a traceability chain to the international System of Units (SI), a primary reference measurement procedure is needed, defined as a procedure which includes a complete analysis of influence quantities and perturbing factors and a complete description of measurement uncertainties. We describe a primary reference measurement procedure for the determination of erythrocyte concentration, based on flow cytometric cell counting by impedance measurements. To correct for instrument- and sample-dependent counting loss due to random coincidences, dilution series are prepared. The reference quantity value of the cell concentration is derived by extrapolation to vanishing volume fraction of the sample in the measurement suspension. Typically, for erythrocyte and leucocyte concentrations respective uncertainties of approximately 0.75% and 2% are reached. Future developments concern the extension of the procedures validated for erythrocyte and leucocyte counting by including immunological staining and microscopic techniques.

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Assessment of Digital PCR as a Primary Reference Measurement Procedure to Support Advances in Precision Medicine

Clinical Chemistry ◽

10.1373/clinchem.2017.285478 ◽

2018 ◽

Vol 64 (9) ◽

pp. 1296-1307 ◽

Cited By ~ 18

Author(s):

Alexandra S Whale ◽

Gerwyn M Jones ◽

Jernej Pavšič ◽

Tanja Dreo ◽

Nicholas Redshaw ◽

...

Keyword(s):

Precision Medicine ◽

Copy Number ◽

Digital Pcr ◽

Measurement Procedure ◽

Patient Treatment ◽

Molecular Diagnostic ◽

Reference Measurement ◽

Reference Measurement Procedure ◽

Wide Range ◽

Primary Reference

Abstract BACKGROUND Genetic testing of tumor tissue and circulating cell-free DNA for somatic variants guides patient treatment of many cancers. Such measurements will be fundamental in the future support of precision medicine. However, there are currently no primary reference measurement procedures available for nucleic acid quantification that would support translation of tests for circulating tumor DNA into routine use. METHODS We assessed the accuracy of digital PCR (dPCR) for copy number quantification of a frequently occurring single-nucleotide variant in colorectal cancer (KRAS c.35G>A, p.Gly12Asp, from hereon termed G12D) by evaluating potential sources of uncertainty that influence dPCR measurement. RESULTS Concentration values for samples of KRAS G12D and wild-type plasmid templates varied by <1.2-fold when measured using 5 different assays with varying detection chemistry (hydrolysis, scorpion probes, and intercalating dyes) and <1.3-fold with 4 commercial dPCR platforms. Measurement trueness of a selected dPCR assay and platform was validated by comparison with an orthogonal method (inductively coupled plasma mass spectrometry). The candidate dPCR reference measurement procedure showed linear quantification over a wide range of copies per reaction and high repeatability and interlaboratory reproducibility (CV, 2%–8% and 5%–10%, respectively). CONCLUSIONS This work validates dPCR as an SI-traceable reference measurement procedure based on enumeration and demonstrates how it can be applied for assignment of copy number concentration and fractional abundance values to DNA reference materials in an aqueous solution. High-accuracy measurements using dPCR will support the implementation and traceable standardization of molecular diagnostic procedures needed for advancements in precision medicine.

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