Browsing by Author "Roraas, Thomas"

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A checklist for critical appraisal of studies of biological variation
(2014-01-01) Bartlett, William A.; Braga, Federica; Carobene, Anna; Coskun, Abdurrahman; Prusa, Richard; Fernandez-Calle, Pilar; Roraas, Thomas; Jonker, Neils; Sandberg, Sverre; Grp, Biol Variation Working; Chem, European Federation Clinical
Data on biological variation are used for many purposes in laboratory medicine but concern exists over the validity of the data reported in some studies. A critical appraisal checklist has been produced by a working group established by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) to enable standardised assessment of existing and future publications of biological variation data. The checklist identifies key elements to be reported in studies to enable safe accurate and effective transport of biological variation data sets across healthcare systems. The checklist is mapped to the domains of a minimum data set required to enable this process.
Biological Variation Estimates Obtained from 91 Healthy Study Participants for 9 Enzymes in Serum
(AMER ASSOC CLINICAL CHEMISTRY, 2017-01-01) Carobene, Anna; Roraas, Thomas; Solvik, Una Orvim; Sylte, Marit Sverresdotter; Sandberg, Sverre; Guerra, Elena; Marino, Irene; Jonker, Niels; Barla, Gerhard; Bartlett, William A.; Fernandez-Calle, Pilar; Diaz-Garzon, Jorge; Tosato, Francesca; Plebani, Mario; Coskun, Abdurrahman; Serteser, Mustafa; Unsal, Ibrahim; Ceriottil, Ferruccio; Biological, E.F.L.M. Working Grp
BACKGROUND: We sought to develop estimates of biological variation (BV) for 9 enzymes in blood serum as part of the European Biological Variation Study. METHODS: Ninety-one healthy study participants (38 male and 53 female, 21-69 years old) were phlebotomized in each of 10 consecutive weeks at 6 European laboratories. The same preanalytical sample-handling protocol was followed at each center before transport to San Raffaele Hospital, Milan, Italy, for analysis. Sera were stored at -80 degrees C before analysis in duplicate within a single run on an ADVIA 2400 Clinical Chemistry System (Siemens Healthcare) following a protocol designed to minimize analytical imprecision. Assay traceability was established using frozen sera with target values assigned by reference methods. The results were subjected to outlier analysis before CV-ANOVA to deliver valid BV estimates. Results for 9 enzymes were subsequently partitioned for graphical display allowing visual assessment of the effects of country of origin, sex, and age on BV estimates. RESULTS: We found no effect of country upon the observed variation, but overall sex-related differences were evident for alanine amino transferase (ALT), gamma-glutamyl transferase (GGT), and creatine kinase (CK). The following estimates for within-subject BV (CVI) and between-subject BV (CVG), respectively, were obtained: ALT: 9.3\%, 28.2\%
Harmonization initiatives in the generation, reporting and application of biological variation data
(2018-01-01) Aarsand, Aasne K.; Roraas, Thomas; Bartlett, William A.; Coskun, Abdurrahman; Carobene, Anna; Fernandez-Calle, Pilar; Jonker, Niels; Diaz-Garzon, Jorge; Braga, Federica; Sandberg, Sverre; Chem, European Federation Clinical
Biological variation (BV) data have many applications in laboratory medicine. However, concern has been raised that some LW estimates in use today may be irrelevant or of unacceptable quality. A number of initiatives have been launched by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) and other parties to deliver a more harmonized practice in the generation, reporting and application of BV data. Resulting from a necessary focus upon the veracity of historical BV studies, critical appraisal and meta-analysis of published BV studies is possible through application of the Biological Variation Data Critical Appraisal Checklist (BIVAC), published in 2017. The BIVAC compliant large-scale European Biological Variation Study delivers updated high-quality BV data for a wide range of measurands. Other significant developments include the publication of a Medical Subject Heading term for BV and recommendations for common terminology for reporting of BV data. In the near future, global BV estimates derived from meta-analysis of BIVAC appraised publications will be accessible in a Biological Variation Database at the EFLM website. The availability of these high-quality data, which have many applications that impact on the quality and interpretation of clinical laboratory results, will afford improved patient care.
The Biological Variation Data Critical Appraisal Checklist: A Standard for Evaluating Studies on Biological Variation
(AMER ASSOC CLINICAL CHEMISTRY, 2018-01-01) Aarsand, Aasne K.; Roraas, Thomas; Fernandez-Calle, Pilar; Ricos, Carmen; Diaz-Garzon, Jorge; Jonker, Niels; Perich, Carmen; Gonzalez-Lao, Elisabet; Carobene, Anna; Minchinela, Joana; Coskun, Abdurrahman; Simon, Margarita; Alvarez, Virtudes; Bartlett, William A.; Fernandez-Fernandez, Pilar; Boned, Beatriz; Braga, Federica; Corte, Zoraida; Aslan, Berna; Sandberg, Sverre; Chem, European Federation Clinical; Variation, Working Grp Biological; Biological, Task \& Finish Grp
BACKGROUND: Concern has been raised about the quality of available biological variation (BV) estimates and the effect of their application in clinical practice. A European Federation of Clinical Chemistry and Laboratory Medicine Task and Finish Group has addressed this issue. The aim of this report is to (a) describe the Biological Variation Data Critical Appraisal Checklist (BIVAC), which verifies whether publications have included all essential elements that may impact the veracity of associated BV estimates, (b) use the BIVAC to critically appraise existing BV publications on enzymes, lipids, kidney, and diabetes-related measurands, and (c) apply metaanalysis to deliver a global within-subject BV (CVI) estimate for alanine aminotransferase (ALT). METHODS: In the BIVAC, publications were rated as A, B, C, or D, indicating descending compliance for 14 BIVAC quality items, focusing on study design, methodology, and statistical handling. A D grade indicated that associated BV estimates should not be applied in clinical practice. Systematic searches were applied to identify BV studies for 28 different measurands. RESULTS: In total, 128 publications were identified, providing 935 different BV estimates. Nine percent achieved D scores. Outlier analysis and variance homogeneity testing were scored as C in >60\% of 847 cases. Metaanalysis delivered a CVI estimate for ALT of 15.4\%. CONCLUSIONS: Application of BIVAC to BV publications identified deficiencies in required study detail and delivery, especially for statistical analysis. Those deficiencies impact the veracity of BV estimates. BV data from BIVAC-compliant studies can be combined to deliver robust global estimates for safe clinical application. (c) 2017 American Association for Clinical Chemistry
The EuBIVAS Project: Within- and Between-Subject Biological Variation Data for Serum Creatinine Using Enzymatic and Alkaline Picrate Methods and Implications for Monitoring
(AMER ASSOC CLINICAL CHEMISTRY, 2017-01-01) Carobene, Anna; Marino, Irene; Coskun, Abdurrahman; Serteser, Mustafa; Unsal, Ibrahim; Guerra, Elena; Bartlett, William A.; Sandberg, Sverre; Aarsand, Aasne Karine; Sylte, Marit Sverresdotter; Roraas, Thomas; Solvik, Una Orvim; Fernandez-Calle, Pilar; Diaz-Garzon, Jorge; Tosato, Francesca; Plebani, Mario; Jonker, Niels; Barla, Gerhard; Ceriotti, Ferruccio; Variation, E.F.L.M. Working Grp Biol
BACKGROUND: The European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) European Biological Variation Study (EuBIVAS) has been established to deliver rigorously determined biological variation (BV) indices. EuBIVAS determined BV for serum creatinine using the enzymatic and alkaline picrate measurement methods. METHOD: In total, 91 healthy individuals (38 males, 53 females
The EuBIVAS: Within- and Between-Subject Biological Variation Data for Electrolytes, Lipids, Urea, Uric Acid, Total Protein, Total Bilirubin, Direct Bilirubin, and Glucose
(AMER ASSOC CLINICAL CHEMISTRY, 2018-01-01) Aarsand, Aasne K.; Diaz-Garzon, Jorge; Fernandez-Calle, Pilar; Guerra, Elena; Locatelli, Massimo; Bartlett, William A.; Sandberg, Sverre; Roraas, Thomas; Ceriotti, Ferruccio; Solvik, Una Orvim; Sylte, Marit Sverresdotter; Coskun, Abdurrahman; Serteser, Mustafa; Unsal, Ibrahim; Tosato, Francesca; Plebani, Mario; Jonker, Niels; Barla, Gerhard; Carobene, Anna; Chem, European Federation Clinical
BACKGROUND: The European Federation of Clinical Chemistry and Laboratory Medicine European Biological Variation Study (EuBIVAS) has been established to deliver rigorously determined data describing biological variation (BV) of clinically important measurands. Here, EuBIVAS-based BV estimates of serum electrolytes, lipids, urea, uric acid, total protein, total bilirubin, direct bilirubin, and glucose, as well as their associated analytical performance specifications (APSs), are presented. METHOD: Samples were drawn from 91 healthy individuals (38 male, 53 female
The European Biological Variation Study (EuBIVAS): Biological Variation Data for Coagulation Markers Estimated by a Bayesian Model
(OXFORD UNIV PRESS INC, 2021-01-01) Aarsand, Aasne K.; Kristoffersen, Ann Helen; Sandberg, Sverre; Stove, Bard; Coskun, Abdurrahman; Fernandez-Calle, Pilar; Diaz-Garzon, Jorge; Guerra, Elena; Ceriotti, Ferruccio; Jonker, Niels; Roraas, Thomas; Carobene, Anna; Chem, European Federation Clinical
BACKGROUND: For biological variation (BV) data to be safely used, data must be reliable and relevant to the population in which they are applied. We used samples from the European Biological Variation Study (EuBIVAS) to determine BV of coagulation markers by a Bayesian model robust to extreme observations and used the derived within-participant BV estimates {[}CVP(i)] to assess the applicability of the BV estimates in clinical practice. METHOD: Plasma samples were drawn from 92 healthy individuals for 10 consecutive weeks at 6 European laboratories and analyzed in duplicate for activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen, D-dimer, antithrombin (AT), protein C, protein S free, and factor VIII (FVIII). A Bayesian model with Student t likelihoods for samples and replicates was applied to derive CVP(i) and predicted BV estimates with 95\% credibility intervals. RESULTS: For all markers except D-dimer, CVP( i) were homogeneously distributed in the overall study population or in subgroups. Mean within-subject estimates (CVI) were <5\% for APTT, PT, AT, and protein S free, <10\% for protein C and FVIII, and <12\% for fibrinogen. For APTT, protein C, and protein S free, estimates were significantly lower in men than in women <= 50 years. CONCLUSION: For most coagulation markers, a common CVI estimate for men and women is applicable, whereas for APTT, protein C, and protein S free, sex-specific reference change values should be applied. The use of a Bayesian model to deliver individual CVP(i) allows for improved interpretation and application of the data.