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  • 1
    Online Resource
    Online Resource
    Age dependence of within-subject biological variation of nine common clinical chemistry analytes
    Walter de Gruyter GmbH ; 2012
    In:  Clinical Chemistry and Laboratory Medicine Vol. 50, No. 5 ( 2012-05-01)
    Details
    In: Clinical Chemistry and Laboratory Medicine, Walter de Gruyter GmbH, Vol. 50, No. 5 ( 2012-05-01)
    Abstract: The knowledge of biological variation (BV) data is important for clinical decisions and as a basis for defining analytical quality specifications. However, in gene\xadrating reliable data of biological variation there are still some unsolved problems, such as age dependence. The aim of our work is to verify this aspect. Twenty-six subjects divided into three groups by age were studied. Blood samples were collected in lithium heparin tubes for four weeks at one week intervals, on the same day of the week (Tuesday) and at the same time of day (8–9 a.m.) by the same phlebotomist. They were analysed in duplicate for creatinine, urate, calcium, albumin, total cholesterol, high density lipoprotein (HDL) and low density lipoprotein (LDL)-cholesterol, triglycerides and iron. After outlier exclusion by Cochran\u2019s test, components of biological variation were calculated by ANOVA. The significance of the differences between results of the classes was also calculated with the Student\u2019s test (t-test) and the Fisher\u2019s test (F-test). Excluding albumin, the group 3 results (age range from 78 to 98 years) showed significantly lower CV within subjects (CV Our data seem to highlight the relevance of the age when choosing the reference subjects for biological variation studies. The level of within-subject biological variation of the elderly group may have been further reduced by the homogeneity of the group constituted by individuals living together in the same nursing home.
    Type of Medium: Online Resource
    ISSN: 1437-4331 , 1434-6621
    URL: Article
    DOI: 10.1515/cclm-2011-0868
    Language: Unknown
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2012
    detail.hit.zdb_id: 1492732-9
    SSG: 15,3
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  • 2
    Online Resource
    Online Resource
    A pragmatic proposal for permissible limits in external quality assessment schemes with a compromise between biological variation and the state of the art
    Walter de Gruyter GmbH ; 2012
    In:  Clinical Chemistry and Laboratory Medicine Vol. 50, No. 5 ( 2012-05-01)
    Details
    In: Clinical Chemistry and Laboratory Medicine, Walter de Gruyter GmbH, Vol. 50, No. 5 ( 2012-05-01)
    Abstract: Permissible limits for internal and external quality assurance are either based on biological variation or on the state of the art (technical feasibility). The former approach has a scientific basis, but, in some cases, leads to limits which are either not achievable under the present technology, or which are not stringent enough. If proficiency testing is mandatory, stringent limits which cannot be fulfilled by the majority of laboratories could lead to juristic consequences. Therefore, most national guidelines were based on the state of the art, however, without providing the underlying reasoning. A simple algorithm for permissible limits in external quality assessment schemes (EQAS) is proposed based on biological variation, technical feasibility and correlated to the rate of false positive results. The proposed limits are compared with some limits from several EQAS (RiliBÄK, SEKK, RCPA, CLIA, PROLARIT). The suggested limits are slightly more stringent than the German RiliBÄK, less stringent than the Australasian guidelines and agreed best with the Czech SEKK and the Italian PROLARIT scheme. The graphical presentation of permissible limits strictly derived of biological variation with the proposed limits led to straight lines with different slopes and a cross-over at the limits for quantities with a medium biological variation (e.g., trijodthyronine). The greatest discordance between the various recommendations was observed for calcium, chloride, hemoglobin A
    Type of Medium: Online Resource
    ISSN: 1437-4331 , 1434-6621
    URL: Article
    DOI: 10.1515/cclm-2011-0862
    Language: Unknown
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2012
    detail.hit.zdb_id: 1492732-9
    SSG: 15,3
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  • 3
    Online Resource
    Online Resource
    A systematic review of data on biological variation for alanine aminotransferase, aspartate aminotransferase and γ-glutamyl transferase
    Walter de Gruyter GmbH ; 2013
    In:  Clinical Chemistry and Laboratory Medicine (CCLM) Vol. 51, No. 10 ( 2013-10-01), p. 1997-2007
    Details
    In: Clinical Chemistry and Laboratory Medicine (CCLM), Walter de Gruyter GmbH, Vol. 51, No. 10 ( 2013-10-01), p. 1997-2007
    Abstract: Background: Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyl transferase (GGT) are enzymes measured in serum or plasma to investigate liver disease. The aim of this work is to assess the validity of published biological variation (BV) data currently available for these enzymes. Methods: Publications containing BV data for ALT, AST and GGT were identified by searching PubMed using the following keywords: biological varia*, RCV, CV w , CV i , CV b , and CV g . The 95% confidence intervals for the within- and between-subject coefficients of variation were calculated using the analytical imprecision, the number of subjects, samples and replicates. Results: The searches identified 10 publications with ALT, 14 with AST and nine with GGT data. The protocols presented in those publications as used were varied. The ranges of within-subject variation reported were: ALT: 11.1%–58.1%, AST: 3.0%–32.3% and for GGT: 3.9%–14.5%. The median values (ALT: 18.0%, AST: 11.9% and GGT: 13.8%) were similar to those listed in a BV database commonly used as a reference source. Conclusions: Published BV data for ALT, AST and GGT demonstrate a wide range of values derived from inconsistent protocols. The quality of the presentations of the data is variable. These findings raise concerns around the utility of the data currently available and highlight the need for critical appraisal of such publications. The working group on BV of the European Federation of Clinical Chemistry and Laboratory Medicine is undertaking work to develop a critical appraisal checklist for the production and publication of reliable BV data.
    Type of Medium: Online Resource
    ISSN: 1437-4331 , 1434-6621
    URL: Article
    DOI: 10.1515/cclm-2013-0096
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2013
    detail.hit.zdb_id: 1492732-9
    SSG: 15,3
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  • 4
    Online Resource
    Online Resource
    Comparison of the results from two different External Quality Assessment Schemes supports the utility of robust quality specifications
    Walter de Gruyter GmbH ; 2011
    In:  cclm Vol. 49, No. 7 ( 2011-07-01), p. 1143-1149
    Details
    In: cclm, Walter de Gruyter GmbH, Vol. 49, No. 7 ( 2011-07-01), p. 1143-1149
    Abstract: Background: The definition of quality goals to evaluate the performance of laboratories participating in External Quality Assessment Schemes (EQAS) is currently not homogeneous. The aim of the work was to verify the applicability of quality goals based on biological variation comparing the results from two different EQAS. Methods: We evaluated the performance of the laboratories participating in two Italian EQAS, presenting similar characteristics in terms of number of participants, type of EQA-samples, and program organization. The results were obtained during 2007 for 27 components in the regional scheme of Lombardy (RGL) and in the national scheme of Prolarit (PRL). The percentage total error of single measurements was calculated for each reported EQA value. The total error values at the 68th percentile, at selected critical concentration values, were compared with maximum tolerable error derived from biological variation. Results: The performance of laboratories participating in the RGL scheme was significantly better. The frequency of satisfactory performance at, respectively, minimum, desirable and optimum levels was 98%, 80% and 59% in the RGL scheme, and 73%, 56% and 22% in the PRL scheme. Conclusions: Due to the different performance shown in the two programs, objective analytical goals based on biological variability constitute the optimal solution.
    Type of Medium: Online Resource
    ISSN: 1437-4331 , 1434-6621
    URL: Article
    DOI: 10.1515/CCLM.2011.196
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2011
    detail.hit.zdb_id: 1492732-9
    SSG: 15,3
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  • 5
    Online Resource
    Online Resource
    Evaluation of the impact of standardization process on the quality of serum creatinine determination in Italian laboratories
    Elsevier BV ; 2014
    In:  Clinica Chimica Acta Vol. 427 ( 2014-01), p. 100-106
    Details
    In: Clinica Chimica Acta, Elsevier BV, Vol. 427 ( 2014-01), p. 100-106
    Type of Medium: Online Resource
    ISSN: 0009-8981
    URL: Article
    DOI: 10.1016/j.cca.2013.10.001
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2014
    detail.hit.zdb_id: 1499920-1
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  • 6
    Online Resource
    Online Resource
    A mechanism-based way to evaluate commutability of control materials for enzymatic measurements. The example of gamma-glutamyltransferase
    Elsevier BV ; 2013
    In:  Clinica Chimica Acta Vol. 424 ( 2013-09), p. 153-158
    Details
    In: Clinica Chimica Acta, Elsevier BV, Vol. 424 ( 2013-09), p. 153-158
    Type of Medium: Online Resource
    ISSN: 0009-8981
    URL: Article
    DOI: 10.1016/j.cca.2013.06.012
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2013
    detail.hit.zdb_id: 1499920-1
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