Role of Reference Materials and Reference Methods in the Measurement Process

Uriano, George A.; Cali, J. Paul

doi:10.1021/bk-1977-0063.ch004

Cited by 17 publications

(5 citation statements)

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“…8 Measures can be categorized according to a hierarchy of accuracy: definitive, reference, and field (ie, routine). 11 A definitive measure, sometimes called a gold-standard measure, relies on first principles (ie, the fundamental and self-evident basis) to achieve high accuracy; that is, with little or no error, and it reflects in a fundamental way the theoretical structure of the property it purports to represent. A reference measure directly and closely relates to the property of interest, but typically does not reflect the fundamental theoretical structure of the property as closely as does a definitive measure.…”

Section: Research Snapshotmentioning

confidence: 99%

“…Ideally the accuracy of a reference measure is demonstrated by comparison to a definitive measure. 11 A field measure is usually fast, routine, and inexpensive, requiring relatively unsophisticated personnel and technology. Accuracy of a field measure is often best demonstrated by comparison to a reference measure (or definitive measure when available).…”

Section: Research Snapshotmentioning

confidence: 99%

“…Accuracy of a field measure is often best demonstrated by comparison to a reference measure (or definitive measure when available). 11 For example, in assessment of body composition, specifically the property of the percentage of the body that is fat, definitive measures of the composition of body tissues have come from cadaver studies. 12 Reference measures include densitometry, potassium-40 counting, and dual-energy x-ray absorptiometry.…”

Section: Research Snapshotmentioning

confidence: 99%

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Establishing Validity and Cross-Context Equivalence of Measures and Indicators

Frongillo

Baranowski

Subar

et al. 2019

Journal of the Academy of Nutrition and Dietetics

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Quantitative research depends on using measures to collect data that are valid (ie, reflect well the phenomena of interest) and perform equivalently across contexts. Demonstrating validity and cross-context equivalence requires specifically designed studies, but many such studies have problems that have limited their usefulness. This article explains validity and cross-context equivalence of measures (and important related concepts) and clarifies how to establish them. Validation is the process of determining whether a measure or indicator is suitable for providing useful analytical measurement for a given purpose and context. Cross-context equivalence means that a measure performs comparably across contexts. Four types of equivalence are construct, item, measurement, and scalar. Establishing validity and cross-context equivalence requires representing mathematically the errors (ie, imprecision, undependability, and inaccuracy) of a measure and using appropriate statistical methods to quantify these errors. Studies aiming to provide evidence about the validity of a measure need to clarify the purpose and context for use of that measure. Choose one of the two conceptual systems for validation; obtain data to establish the extent to which the measure is well constructed, reliable, and accurate; and use analytic methods beyond simple correlations to provide a basis for making reasoned judgment about whether the measure provides useful analytic measurement for the particular purpose(s) and context. Establishing accuracy of a measure requires having available other measures known to be accurate as comparators; in the case that no other measure understood to be more accurate is available, then the study will be able to establish agreement rather than validity.

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Section: Research Snapshotmentioning

confidence: 99%

Section: Research Snapshotmentioning

confidence: 99%

Section: Research Snapshotmentioning

confidence: 99%

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Establishing Validity and Cross-Context Equivalence of Measures and Indicators

Frongillo

Baranowski

Subar

et al. 2019

Journal of the Academy of Nutrition and Dietetics

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“…The necessity for and advantages of a metrologically sound reference system for achieving compatibility of assay results in clinical chemistry have been reviewed extensively with regard to analytes common in clinical chemistry (2)(3)(4)(5). In the past, however, coagulation tests have commonly been exempted from evaluation in rigorous metrological terms because of their complexity.…”

Section: Development Of a Reference System For The Components Of The mentioning

confidence: 99%

A Reference System Approach to Future Standardization of Laboratory Tests for Hemostasis, ,

Jackson¹,

White²,

Barrowcliffe³

et al. 2002

Thromb Haemost

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A description of the development of a strategy for improving the standardization of coagulation tests and the rationale behind the recommendations that follow are the subject of this position paper. Such an endeavor has been occasioned by the advances in the technology for the diagnosis and therapeutic treatment of hemorrhagic and thromboembolic diseases. These and anticipated further advances make it imperative that the standardization of laboratory tests used in diagnosis and in monitoring therapeutic treatments be the 'state-of-the-art' so that the accuracy, comparability and clinical utility is of the highest order. The complexity of the hemostatic system makes achieving accuracy and comparability among these tests a substantial challenge. Another impetus for improving the comparability of the results from different laboratories throughout the world arises as a consequence of the globalization of the pharmaceutical and medical diagnostic companies that began in the 1990's and is continuing into this, the 21 st century.The assay of a component of the coagulation system presently employs a "substrate plasma" deficient in the component of interest and the measurement of the elapsed time between initiation of the clotting process and clot formation (gelation). Quantitative assessment of the activity of this component is achieved through a dose-response relationship between a dilution of a reference plasma that contains all coagulation components in their "normal concentrations and the elapsed time (clotting time) for each dilution. Many variations and modifications of this approach that have improved the specificity of these tests are in routine use today. These methods have been key to many of the biochemical advances made in the past and have been invaluable to local laboratories with expertise and understanding of hemostasis. However, coagulation tests are now being passed to contract laboratories where those responsible for performing these assays do not have the necessary background in coagulation.Independent of the need for advancing the art of coagulation testing; the completion of the human genome project will mandate a change in the perspective that must be taken to standardize the protein products that the genome encodes. Phenotypic expression of impaired 1 Hemostasis is intended to be interpreted broadly and to include proteins components of coagulation, fibrinolysis and platelets. 2 Designated C-SCT, Committee on Standardization of Coagulation Tests in the IFCC Scientific Division 3 A decision was made by the C-SCT to exclude the two common or "global" screening tests, the PT and the aPTT and variations of these tests such as the aPTT used for heparin monitoring and in APC resistance detection from this effort. The proposals made here are not intended to apply to these tests, nor have tests related to platelet function been considered.

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“…The term compatibility which is used in metrology 2 ) means the correspondence between measuring methods (13). The analytical results of compatible methods have a similar error structure.…”

Section: Introductionmentioning

confidence: 99%

Reference Methods as a Basis for Accurate Measuring Systems

Büttner

1991

Clinical Chemistry and Laboratory Medicine

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Summary:Reference methods, äs part of a reference System, are essential for improving the accuracy of routine methods. They can help to establish worldwide compatibility of clinical chemical measurements and they provide an objective basis for quality control measures. The subject of analytical errors is treated in detail, then the concept of reference methods is developed. This review emphasizes the fundamental metrological aspects of reference methods and reference measurement technology. An overview is given of the most important analytical principles used for reference methods in clinical chemistry. The particular problems of reference methods for the determination of the catalytic activity concentration of enzymes are outside the scope of this review.

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Role of Reference Materials and Reference Methods in the Measurement Process

Cited by 17 publications

References 0 publications

Establishing Validity and Cross-Context Equivalence of Measures and Indicators

Establishing Validity and Cross-Context Equivalence of Measures and Indicators

A Reference System Approach to Future Standardization of Laboratory Tests for Hemostasis, ,

Reference Methods as a Basis for Accurate Measuring Systems

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