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Biomedical subjects

J Middle

Publications and source records attributed to J Middle.

7 recordsLinked to original sources
PubMed1997

Current stage of standardization of measurements of specific polypeptides and proteins discussed in light of steps needed towards a comprehensive measurement system.

We present a standardization model for the measurement of specific polypeptides and proteins, which is based on an integrated development of all important elements of a reference measurement system. Generally, the model is in line with other current recommendations. However, it puts special emphasis on the definition of the analyte and on the role of reference methods for verification of the standardization process by measurement of patient specimens. Further, we discuss the needs for its implementation in the routine laboratory. In the light of this model, we investigate the current stage of standardization of routine methods for enzymes, peptide hormones, proteins, apolipoproteins, glycohaemoglobin, and tumour markers.

Apolipoproteins↗
PubMed1996

Analytical specifications of reference methods compilation and critical discussion (from the members of the European EQA-Organizers Working Group B).

We present a compilation of published data for accuracy, precision, and measurement design for analytes that, currently, are of major interest for European reference laboratories. These data are compared with recent recommendations for performance of reference methods to be used within networks of European reference laboratories. In addition, we review the literature on reference methods and related topics.

Blood Glucose↗
PubMed1995

Analytical quality specifications for reference methods and operating specifications for networks of reference laboratories. discussion paper from the members of the external quality assessment (EQA) Working Group B1) on target values in EQAS.

The aim of the Working Group was to describe guidelines for the establishment of networks of reference laboratories. The need for such networks to achieve an accuracy-based uniform measurement system with traceability of results of analytical systems/test-kits to the true value is outlined. Criteria for analytical quality specifications, which are related to the ultimate purpose of the reference method and thereby to the objectives of the networks, are emphasized. The group recommends the use of two models: one based on specifications for routine methods, which are dictated by the biological variations of the respective analytes, the second respecting the analytical state-of-the-art of reference methodology. Further, the group presents operating specifications for networks that guarantee the continuous performance of reference method measurements whilst maintaining a uniform and stable level of quality.

Chemistry, Clinical↗
PubMed1993

Standardization of hapten immunoprocedures: total cortisol.

The broad objectives of this report are to enhance the clinical utility of the results of hapten measurement immunoprocedures by encouraging standardization of the procedures. It was decided to restrict the subject of the report to one analyte, and cortisol was chosen because of its diagnostic importance, the need for improved comparability with routine procedures, and its relevance to many other analytes. Therefore, the immediate objectives are to improve the clinical utility of total serum cortisol concentrations measured on different occasions and in different laboratories, to make diagnostic reference intervals more reliable and widely applicable, and to improve diagnostic accuracy by: Improving the agreement between results from reference measurement procedures and the results obtained with normal routine immunoprocedures for the measurement of total serum cortisol, and hence the comparability of routine results; and Reducing the susceptibility of the immunoprocedures to crossreactivity and interference. It is recognized that good comparability of results depends on procedures which are specific, properly calibrated and validated, and that the most important factors are resistance to crossreactants and interferants. Analytical goals for cortisol immunoprocedures are zero bias for 'all' samples with respect to a reference procedures, with the total analytical standard deviation equal to, or less than, half the within-individual standard deviation for cortisol, or 7.6% according to a recent estimate. To these ends the group proposes the following measures: 1. An international network of reference laboratories for cortisol measurement should be established, and progressively developed to include other hapten analytes. The service of the participating laboratories would be necessary to make feasible other recommendations listed below. 2. Procedures should be comprehensively validated, including a thorough crossreactivity study with the results presented to indicate the possible significance of each crossreactivity, a direct comparison of results with those obtained by a reference procedure for an adequate number of varied fresh/frozen patient samples, and suitable clinical validation studies. 3. External quality assessment schemes should assess participating laboratory performance against reference procedure values, and not consensus values related to values determined by any group of participating procedures. They should also assess the ability to determine added standard and to resist common interferants. 4. Master calibrators for use in the production of calibrators included in commercial kits, and formulated identically to these, should be certified with at least one reference measurement procedure, so that the concentrations of analyte in calibrators can be traced back to concentrations determined by a reference procedure.(ABSTRACT TRUNCATED AT 400 WORDS)

Humans↗