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Iskalni niz: "avtor" (Pika Meško-Brguljan) .

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1.
Documenting metrological traceability as intended by ISO 15189:2012 : a consensus statement about the practice of the implementation and auditing of this norm element
Maria Lohmander, Christos Kroupis, Edward Barrett, Guilaine Boursier, Bernard Gouget, Pika Meško-Brguljan, Florent Vanstapel, Marc H. M. Thelen, Luděk Šprongl, Tatjana Vodnik, 2019

Povzetek: ISO15189:2012 requires medical laboratories to document metrological traceability of their results. While the ISO17511:2003 standard on metrological traceability in laboratory medicine requires the use of the highest available level in the traceability chain, it recognizes that for many measurands there is no reference above the manufacturer's selected measurement procedure and the manufacturer's working calibrator. Some immunoassays, although they intend to measure the same quantity and may even refer to the same reference material, unfortunately produce different results because of differences in analytical selectivity as manufacturers select different epitopes and antibodies for the same analyte. In other cases, the cause is the use of reference materials, which are not commutable. The uncertainty associated with the result is another important aspect in metrological traceability implementation. As the measurement uncertainty on the clinical samples is influenced by the uncertainty of all steps higher in the traceability chain, laboratories should be provided with adequate and appropriate information on the uncertainty of the value assignment to the commercial calibrators that they use. Although the between-lot variation in value assignment will manifest itself as part of the long-term imprecision as estimated by the end-user, information on worst-case to be expected lot-lot variation has to be communicated to the end-user by the IVD provider. When laboratories use ancillary equipment that potentially could have a critical contribution to the reported results, such equipment needs verification of its proper calibration and criticality to the result uncertainty could be assessed by an approach based on risk analysis, which is a key element of ISO15189:2012 anyway. This paper discusses how the requirement for metrological traceability as stated in ISO15189 should be met by the medical laboratory and how this should be assessed by accreditation bodies.
Ključne besede: laboratories, medical laboratory science, risk management, quality control, quality improvement, health care quality assurance, metrological traceability
DiRROS - Objavljeno: 22.10.2020; Ogledov: 666; Prenosov: 120

2.
Validation and verification of examination procedures in medical laboratories : opinion of the EFLM Working Group Accreditation and ISO/CEN standards (WG-A/ISO) on dealing with ISO 15189:2012 demands for method verification and validation
Pika Meško-Brguljan, Solveig Linko, Çiğdem Sönmez, Michel Vaubourdolle, Ines Vukasović, Wim Huisman, Florent Vanstapel, Tatjana Vodnik, Roseri Roelofsen-de Beer, Jos Wielders, Guilaine Boursier, 2020

Povzetek: This paper reflects the opinion of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group Accreditation and ISO/CEN standards (WG-A/ISO). It aims to provide guidance for drawing up local/national documents about validation and verification of laboratory methods. We demonstrate how risk evaluation can be used to optimize laboratory policies to meet intended use requirements as well as requirements of standards. This is translated in a number of recommendations on how to introduce risk evaluation in various stages of the implementation of new methods ultimately covering the whole process cycle.
Ključne besede: opinion paper, EFLM, ISO 15189:2012, validation, verification
DiRROS - Objavljeno: 10.08.2020; Ogledov: 849; Prenosov: 245

3.
Carboxypeptidase cathepsin X defines a multifunctional role of gamma-enolase in cancer
Tjaša Vižin, Anja Pišlar, Ib Jarle Christensen, Hans Jørgen Nielsen, Pika Meško-Brguljan, Janko Kos, 2022

Povzetek: Gamma-enolase enzymatic activity is involved in glycolysis, a prevalent process in cancer cell metabolism. Additionally, gamma-enolase has a pro-survival function, exhibited through the active site at the C-terminal end of the molecule. This activity is regulated by cysteine peptidase cathepsin X, which cleaves two amino acids at C-terminal end of gamma-enolase. In clinical practice, the determination of gamma-enolase as a tumour marker does not differ between total, uncleaved and C-terminally cleaved forms. However, levels of uncleaved gamma-enolase alone may provide additional clinical information. In this study we analysed cathepsin X, C- terminally uncleaved and total gamma-enolase in tumour cell lines and sera from 255 patients with colorectal cancer (CRC) by western blot, immunoprecipitation, enzymatic activity, ELISAs and ECLIA. Results show that uncleaved gamma-enolase, rather than total gamma- enolase, exhibits different levels in cells, being the highest in those, derived from metastatic sites or highly invasive tumours. Gamma-enolase is secreted into the extracellular space predominantly as an uncleaved form and levels were congruent to those within the cells. Furthermore, levels of uncleaved gamma-enolase in cells are inversely related to cathepsin X protein level and its enzymatic activity. Uncleaved gamma-enolase is also predominant form in sera of patients with CRC. Both forms exhibit similar stage dependent distribution, with slightly elevated levels in stage IV patients. Higher levels of total gamma-enolase are significantly related to shorter survival in patients with metastatic CRC. Results support evidence of additional pro-survival function of gamma-enolase in cancer. Future studies should focus on analysis of uncleaved gamma-enolase in tumour samples, which may provide additional relations to clinical indicators of disease progression.
Ključne besede: cancer, cathepsin X, cell survival, gamma-enolase, prognosis
DiRROS - Objavljeno: 06.04.2022; Ogledov: 95; Prenosov: 74
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