scholarly journals Progress and impact of enzyme measurement standardization

Author(s):  
Ilenia Infusino ◽  
Erika Frusciante ◽  
Federica Braga ◽  
Mauro Panteghini

AbstractInternational Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has established reference measurement procedures (RMPs) for the most popular enzymes. Manufacturers should assign values to commercial calibrators traceable to these RMPs to achieve equivalent results in clinical samples, independent of reagent kits, instruments, and laboratory where the measurement is carried out. The situation is, however, far from acceptable. Some manufacturers continue to market assays giving results that are not traceable to internationally accepted RMPs. Meanwhile, end-users often do not abandon assays with demonstrated insufficient quality. Of the enzyme measurements, creatine kinase (CK) is satisfactorily standardized and a substantial improvement in performance of marketed γ-glutamyltranspeptidase (GGT) assays has been demonstrated. Conversely, aminotransferase measurements often exceed the desirable analytical performance because of the lack of pyridoxal-5-phosphate addition in the commercial reagents. Measurements of lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and α-amylase (AMY) still show major disagreement, suggesting the need for improvement in implementing traceability to higher-order references. This is mainly the result of using assays with different analytical selectivities for these enzymes. The definition by laboratory professionals of the clinically acceptable measurement uncertainty for each enzyme together with the adoption by EQAS of commutable materials and use of an evaluation approach based on trueness represent the way forward for reaching standardization in clinical enzymology.

2019 ◽  
Vol 57 (7) ◽  
pp. 967-973 ◽  
Author(s):  
Federica Braga ◽  
Mauro Panteghini

Abstract Traceability to a common reference ensures equivalence of results obtained by different assays. Traceability is achieved by an unbroken sequence of calibrations, using reference materials (RMs) that must be commutable. Using non-commutable RMs for calibration will introduce a bias in the calibrated method producing incorrect results for clinical samples (CS). Commutability was defined in 1973 as “the ability of an enzyme material to show inter-assay activity changes comparable to those of the same enzyme in human serum” and later extended as a characteristic of all RMs. However, the concept is still poorly understood and appreciated. Commutability assessment has been covered in CLSI guidelines and requires: (a) selection of 20 CS spanning the relevant concentration range; (b) analysis of both RM and CS with the pair of procedures; (c) data elaboration using regression analysis and calculation if RM fall within the 95% prediction interval defined by CS. This approach has been criticized and to improve it The International Federation of Clinical Chemistry and Laboratory Medicine established a working group that recently finalized recommendations. Commutability is also a requirement for the applicability of external quality assessment (EQA) results in the evaluation of the performance of participating laboratories in terms of standardization of their measurements. Unfortunately, EQA materials are usually not validated for commutability.


2019 ◽  
Vol 57 (5) ◽  
pp. 623-632 ◽  
Author(s):  
Paul O. Collinson ◽  
Amy K. Saenger ◽  
Fred S. Apple ◽  

AbstractThe International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) formed a Task Force on the Application of Cardiac Bio-markers (TF-CB) in 2008, re-designated in 2018 as a committee (C-CB), to produce educational materials on cardiac biomarkers. Established in June 2017, definitive tables covering the majority of high-sensitivity, contemporary and point-of-care (POC) cTn assays have been developed by the C-CB and are available on the IFCC website. These tables provide extensive information about assays’ analytical characteristics and encompass information on diagnostic discriminants, particularly the 99th percentiles, as provided by the manufacturers.


2016 ◽  
Vol 44 (01) ◽  
pp. 19-25 ◽  
Author(s):  
G. Köller ◽  
K. Bassewitz ◽  
G. F. Schusser

ZusammenfassungZiel dieser Arbeit war, den Einsatz des Automaten IMMULITE 2000® mit einem immunometrischen Chemolumineszenz-Assay für die Bestimmung von adrenokortikotropem Hormon (ACTH), Insulin und Insulinwachstumsfaktor 1 (IGF-1) zu prüfen und entsprechende Referenzbereiche für Ponys zu berechnen. Material und Methoden: Nachmittags gewonnene Blutproben von 130 Ponys im Alter von 3–32 Jahren wurden auf Insulin, IGF-1 und ACTH untersucht. Die Referenzbereiche wurden nach der Richtlinie EP28-A3C der International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) aus dem Jahr 2010 berechnet. Ergebnisse: Die Präzision für die Messungen an einem Tag lag für Insulin im Mittel bei 3,28%, für IGF-1 bei 1,84% und für ACTH bei 3,35%. Die Tag-zu-Tag-Präzision (Insulin: 3,45%; IGF-1: 2,89%; ACTH: 9,77%) wurde an drei aufeinanderfolgenden Tagen gemessen, wobei die Lagerung der Proben bei 4 °C erfolgte. Es zeigte sich kein signifikanter Verlust der Insulinaktivität bzw. der Konzentrationen von ACTH und IGF-1. Für Insulin und IGF-1 ergaben sich altersunabhängige Referenzbereiche (Insulin: 2,0–21,2 mU/l; IGF-1: 50,2–357,2 μg/l). Dagegen wurde für ACTH ein altersabhängiger Referenzbereich er - mittelt, der bei Ponys im Alter von 3–12 Jahren signifikant niedriger war (4,2–19,8 pg/ml) als bei Ponys im Alter von 13–32 Jahren (5,0–22,6 pg/ml). Schlussfolgerung: Das verwendete Analyseverfahren eignet sich für die Untersuchung von Serumproben von Ponys auf ACTH, IGF-1 und Insulin, doch wird der Einsatz bei der Insulinmessung durch die untere Nachweisgrenze von 2,0 mU/l limitiert. Klinische Relevanz: Die berechneten Referenzbereiche für Insulin und ACTH sind hilfreich für die Diagnostik und Verlaufskontrolle des equinen metabolischen Syndroms und der Pituitary Pars Intermedia Dysfunction (PPID).


Author(s):  
Graham Beastall ◽  
Desmond Kenny ◽  
Paivi Laitinen ◽  
Joop ten Kate

AbstractA definition has been agreed for the most senior professional (consultant) in clinical chemistry and laboratory medicine. A model job description for a consultant has been determined, which is intended to act as a toolkit to assist employing authorities and professional bodies to define the role of individual consultant posts. A total of 86 competences for a consultant have been designated and expressed in the form of simple generic proficiency standards. These competences have been allocated to six broad areas: clinical [13]; scientific [15]; technical [12]; communication [12]; management and leadership [20]; professional autonomy and accountability [14]. The competences are intended to be illustrative rather than definitive and to enable the duties of any consultant post to be defined. Assessment of competence is likely to entail consideration of qualifications, registration status, continuing professional development and performance review. The project is intended as a guide to European societies of clinical chemistry and laboratory medicine. The guide should be capable of local interpretation to encourage a greater degree of commonality in the role of the consultant whilst protecting national identity. The guide should stimulate international understanding and collaboration and contribute to an overall improvement in the quality of practice.


2011 ◽  
Vol 152 (14) ◽  
pp. 555-558
Author(s):  
Gabriella Bekő

A new laboratory standard, specific for HbA1c was prepared by the International Federation of Clinical Chemistry and Laboratory Medicine. Consequently, manufacturers will supply their calibrators with the International Federation of Clinical Chemistry and Laboratory Medicine standard. Laboratories in Hungary switch to this new method in April 1, 2011. After this date, results of HbA1c measurements will be reported in International Federation of Clinical Chemistry and Laboratory Medicine units (mmol/mol) and in the derived National Glycohemoglobin Standardization Program units (%) calculated by master equation from the International Federation of Clinical Chemistry and Laboratory Medicine/National Glycohemoglobin Standardization Program methods. Using the new standardization the HbA1c measurements will be traceable to the International Federation of Clinical Chemistry and Laboratory Medicine reference method and interlaboratory comparisons will be possible. Orv. Hetil., 2011, 152, 555–558.


Author(s):  
Anna Carobene ◽  
Marta Strollo ◽  
Niels Jonker ◽  
Gerhard Barla ◽  
William A. Bartlett ◽  
...  

AbstractBackground:Biological variation (BV) data have many fundamental applications in laboratory medicine. At the 1st Strategic Conference of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) the reliability and limitations of current BV data were discussed. The EFLM Working Group on Biological Variation is working to increase the quality of BV data by developing a European project to establish a biobank of samples from healthy subjects to be used to produce high quality BV data.Methods:The project involved six European laboratories (Milan, Italy; Bergen, Norway; Madrid, Spain; Padua, Italy; Istanbul, Turkey; Assen, The Netherlands). Blood samples were collected from 97 volunteers (44 men, aged 20–60 years; 43 women, aged 20–50 years; 10 women, aged 55–69 years). Initial subject inclusion required that participants completed an enrolment questionnaire to verify their health status. The volunteers provided blood specimens once per week for 10 weeks. A short questionnaire was completed and some laboratory tests were performed at each sampling consisting of blood collected under controlled conditions to provide serum, KResults:Samples from six out of the 97 enroled subjects were discarded as a consequence of abnormal laboratory measurements. A biobank of 18,000 aliquots was established consisting of 120 aliquots of serum, 40 of EDTA-plasma, and 40 of citrated-plasma from each subject. The samples were stored at –80 °C.Conclusions:A biobank of well-characterised samples collected under controlled conditions has been established delivering a European resource to enable production of contemporary BV data.


2005 ◽  
Vol 24 (3) ◽  
pp. 181-186 ◽  
Author(s):  
Gerard Sanders

When quality is referred to in clinical chemistry and laboratory medicine, the focus is mainly on the analytical process. But good professional quality starts with a sound education. In an attempt to describe the practice of clinical chemistry and laboratory medicine in the 15 member states of the "old" European Union, it was noticed that (sometimes) large differences existed in the way professionals are being trained (see: Sanders et al, Clin Chem Lab Med 2002; 40: 196-204). With that outcome, a survey of the Websites of the different Member Societies and Corporate Members of IFCC was conducted. It showed that less than one third of either two groups paid attention to, or offered, education. This led to a series of questions to a non-representative group of colleagues outside the former EU who were willing to give more insight in the educational system of their country. All colleagues were known to be involved actively in clinical chemistry and laboratory medicine. The outcome did not give a uniform pattern, since every country regulates health care in its own way, according to its own historical development, needs, social vision, etc. From that a number of conclusions have been drawn: a. Proper University Training is required to enter vocational training b. Regulated Vocational Training seems to be necessary (4 years) c. A clear Syllabus as an indicative guide to the vocational training is important d. Management training should be included since a clinical chemist will have organizational responsibilities as well e. Examinations may help in improving the quality of the education f. Official Register, recognized by Law, is essential, but not always existing h. Re-Registration can be seen as part of the Quality Cycle. Finally, some attention is being paid to the activities of the EMD. This Division of the IFCC provides the membership of IFCC and the health-care community with education which it considers relevant to Clinical Chemistry and Laboratory Medicine. It is the intention of EMD to improve the quality of the profession by educational activities in molecular biology, evidence based laboratory medicine, quality assurance, distance education, and laboratory management. Specific projects are a Master Course in Laboratory Science, a course in Flowcytometry, and the Visiting Lecturer Program which supports national societies in inviting lecturers on specific topics. More information can be found on the IFCC Web-site (www.ifcc.org). In the future, it is to be expected that emphasis on education in our profession will be on the clinical use of tests, modern media and e-learning, and specific courses in new technologies. EMD works continuously to improve the quality of clinical chemistry and laboratory medicine. The input from all National Societies is appreciated to discern topics most relevant to the membership of IFCC. .


2005 ◽  
Vol 24 (3) ◽  
pp. 157-170
Author(s):  
Nada Majkic-Singh

Medical biochemistry (synonyms: clinical chemistry or clinical biochemistry) in the terms of professional and scientific discipline, stems from and/or has developed along with the natural sciences and its influences (mathematics, physics, chemistry and biochemistry) and medical sciences as well (physiology, genetics, cell biology). As a scientific discipline, medical biochemistry studies metabolic processes of physiological and pathological changes with humans and animals. Applying analytical chemistry's and biochemistry's techniques enables medical biochemists to gain plenty of information related to diagnosis and prognosis which serve physicians to asses the gravity of illness and prescribe healing therapy. Therefore medical biochemistry is an integral part of modern medicine. This discipline was dubbed various, often confusing names such as pathology, physiology, clinical biology, clinical pathology, chemical pathology, clinical biochemistry, medical biochemistry, clinical chemistry and laboratory medicine, all depending on place of origin. The official, internationally accepted name - clinical chemistry, was mentioned for the first time in 1912 by Johan Scherer, who described his laboratory as Clinical Chemistry Laboratory (Klinisch Chemische Laboratorium) in the hospital Julius in Wurzburg in Germany. After creating national societies of clinical chemists, Professor Earl J. King of Royal Postgraduate Medical School from London incited an initiative to unite national societies into the organization with worldwide character - it was the International Association of Clinical Biochemists, monitored by the International Union for Pure and Applied Chemistry (IUPAC). On 24 July 1952 in Paris, a Second International Congress of Biochemistry was held. A year later, in Stockholm, the name of a newly formed association was altered into International Federation of Clinical Chemistry, which was officially accepted in 1955 in Brussels. Today this federation-s name is International Federation for Clinical Chemistry and Laboratory Medicine (IFCC). Right after the World War II our medical biochemists began to gather within their expert societies. Even before 1950 Pharmaceutical Society of Serbia hosted laboratory experts among whom the most active were Prof. Dr. Aleksandar Damanski for bromatology, Prof. Dr. Momcilo Mokranjac for toxicology and Docent Dr. Pavle Trpinac for biochemistry. When the Managing Board of the Pharmaceutical Society of National Republic of Serbia held its session on 22 December 1950, an issue was raised with reference to creation of a Section that would gather together the laboratory experts. Section for Sanitary Chemistry, combining all three profiles of laboratory staff, i.e. medical biochemists, sanitary chemists and toxicologists, was founded on 1st of January 1951. On 15 May 1955, during the sixth plenum of the Society of Pharmaceutical Societies of Yugoslavia (SFRY) held in Split, the decision was passed to set up a Section for Medical Biochemistry in SFDJ. The Section for Medical Biochemistry in SFDJ was renamed into Society for Medical Biochemistry of SFDJ based on the decision passed during the 16th plenum of SFDJ, held on 15 May 1965 in Banja Luka. Pursuant to the decision passed by SMBY on 6 April 1995 and based on the historic data, 15 May was declared as being the official Day of the Society of Medical Biochemists of Yugoslavia. The purpose of YuSMB (currently SMBSCG) is to gather medical biochemists who would develop and enhance all the branches of medical biochemistry in health industry. Its tasks are as following: to standardize operations in clinical-biochemical laboratories, education of young biochemists on all levels, encouraging scientific research, setting up of working norms and implementation, execution and abiding by the ethics codices with health workers. SMBSCG is to promote the systemized standards in the field of medical biochemistry with the relevant federal and republican institutions. SMBSCG is to enable exchange of experiences of its members with the members of affiliate associations in the country and abroad. .


2021 ◽  
Vol 49 (04) ◽  
pp. 234-246
Author(s):  
Elena Theiner ◽  
Corinna Weber ◽  
Elisabeth Müller ◽  
Monica Venner ◽  
Ingrid Vervuert

Zusammenfassung Ziel Etablierung von Referenzintervallen für Mangan (Mn) im Serum, Plasma und Vollblut bei adulten, gesunden Warmblutpferden mit bekannter Mn-Aufnahme und Vergleich von 2 analytischen Methoden der Mn-Bestimmung im Blut. Material und Methoden Zwischen Mai 2018 und November 2019 erfolgte auf 3 Gestüten bei 270 gesunden Pferden im Alter von 3–25 Jahren eine einmalige Blutprobenentnahme. In Vollblut, Plasma (Antikoagulans jeweils Lithium-Heparin [LH]) und Serum wurden die Mn-Konzentrationen mittels Massenspektrometrie mit induktiv gekoppeltem Plasma (ICP-MS) sowie mittels Atomabsorptionsspektrometrie (AAS) bestimmt. Die Referenzintervalle für jedes Substrat wurden nach den Empfehlungen der International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) und des Clinical and Laboratory Standards Institute (CLSI) berechnet (Bereich zwischen 2,5- und 97,5-Perzentil der analysierten Mn-Blutkonzentration). Zeitgleich mit der Blutprobenentnahme wurden repräsentative Futterproben entnommen, um den Mn-Gehalt der korrespondierenden Fütterung zu bestimmen. Ergebnisse Die Pferde zeigten im Vollblut mit einer medianen Mn-Konzentration von 12,4 µg/l (Referenzintervall: 4,99–25,1 µg/l [AAS]; 5,99–25,3 µg/l [ICP-MS]) signifikant höhere Mn-Konzentrationen (p < 0,0001) als im korrespondierenden Serum (Median: 1,65 µg/l, Referenzintervall: 0,60–3,50 µg/l [AAS]; 1,11–2,96 µg/l [ICP-MS]) oder LH-Plasma (Median: 1,35 µg/l, Referenzintervall: 0,22–2,68 µg/l [AAS]; 0,59–2,45 µg/l [ICP-MS]). Im Methodenvergleich ergaben sich für LH-Plasma und Serum zwischen der AAS und der ICP-MS statistisch signifikante Abweichungen in den Mn-Bestimmungen, wohingegen sie für das Vollblut vergleichbare Ergebnisse lieferten. Schlussfolgerung und klinische Relevanz Vollblut weist durchschnittlich 10-fach höhere Mn-Konzentrationen auf als Serum oder LH-Plasma. Bei der Bewertung von Mn-Konzentrationen im Blut muss daher berücksichtigt werden, welches Probenmaterial analysiert wurde und welche Methode zur Anwendung kam, da in Serum und Plasma zwischen AAS und ICP-MS relevante Unterschiede auftreten können.


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