scholarly journals Biological variation and reference change value data for serum copper, zinc and selenium in Turkish adult population

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ceylan Bal ◽  
Serpil Erdogan ◽  
Gamze Gök ◽  
Cemil Nural ◽  
Betül Özbek ◽  
...  
Keyword(s):  
Adult Population ◽  
Reference Intervals ◽  
Serum Copper ◽  
Biological Variation ◽  
Serum Samples ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Copper Zinc ◽  
Clinically Significant ◽  
Analytical Variation

Abstract Objectives Calculation of biological variation (BV) components is very important in evaluating whether a test result is clinically significant. The aim of this study is to analyze BV components for copper, zinc and selenium in a cohort of healthy Turkish participants. Methods A total of 10 serum samples were collected from each of the 15 healthy individuals (nine female, six male), once a week, during 10 weeks. Copper, zinc and selenium levels were analyzed by atomic absorption spectrometer. BV parameters were calculated with the approach suggested by Fraser. Results Analytical variation (CVA), within-subject BV (CVI), between-subject BV (CVG) values were 8.4, 7.1 and 4.3 for copper; 4.2, 9.1 and 13.7 for zinc; 7.6, 2.5 and 6.9 for selenium, respectively. Reference change values (RCV) were 30.46, 27.56 and 22.16% for copper, zinc and selenium, respectively. The index of individuality (II) values were 1.65, 0.66 and 0.36 for copper, zinc and selenium, respectively. Conclusions According to the results of this study, traditional reference intervals can be used for copper but we do not recommend using it for zinc and selenium. We think that it would be more accurate to use RCV value for zinc and selenium in terms of following significant changes in recurrent results of a patient.

Annual biological variation and personalized reference intervals of clinical chemistry and hematology analytes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shuo Wang ◽  
Min Zhao ◽  
Zihan Su ◽  
Runqing Mu
Keyword(s):  
Clinical Chemistry ◽  
Population Based ◽  
Reference Intervals ◽  
Biological Variation ◽  
Annual Data ◽  
Healthy Individuals ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Personalized Diagnosis

Abstract Objectives A large number of people undergo annual health checkup but accurate laboratory criterion for evaluating their health status is limited. The present study determined annual biological variation (BV) and derived parameters of common laboratory analytes in order to accurately evaluate the test results of the annual healthcare population. Methods A total of 43 healthy individuals who had regular healthcare once a year for six consecutive years, were enrolled using physical, electrocardiogram, ultrasonography and laboratory. The annual BV data and derived parameters, such as reference change value (RCV) and index of individuality (II) were calculated and compared with weekly data. We used annual BV and homeostatic set point to calculate personalized reference intervals (RIper) which were compared with population-based reference intervals (RIpop). Results We have established the annual within-subject BV (CVI), RCV, II, RIper of 24 commonly used clinical chemistry and hematology analytes for healthy individuals. Among the 18 comparable measurands, CVI estimates of annual data for 11 measurands were significantly higher than the weekly data. Approximately 50% measurands of II were <0.6, the utility of their RIpop were limited. The distribution range of RIper for most measurands only copied small part of RIpop with reference range index for 8 measurands <0.5. Conclusions Compared with weekly BV, for annual healthcare individuals, annual BV and related parameters can provide more accurate evaluation of laboratory results. RIper based on long-term BV data is very valuable for “personalized” diagnosis on annual health assessments.

Reference intervals and biological variation for kallikrein 6: influence of age and renal failure

2012 ◽  
Vol 50 (5) ◽  
Author(s):  
Eduardo Martínez-Morillo ◽  
Anastasia Diamandis ◽  
Eleftherios P. Diamandis
Keyword(s):  
Renal Failure ◽  
Significant Positive Correlation ◽  
Reference Interval ◽  
Serum Marker ◽  
Reference Intervals ◽  
Biological Variation ◽  
Serum Samples ◽  
Positive Correlation ◽  
Reference Change Value ◽  
Kallikrein 6

AbstractKallikrein 6 (KLK6) is a serine protease involved in numerous cellular processes, up-regulated in many cancers and associated with some neurodegenerative disorders. The aim of this study was to establish a reference interval and estimate the biological variation of KLK6 in serum samples of adults. Furthermore, levels of this protein in patients with renal failure were also studied.Serum samples from healthy volunteers (n=136) were collected. Between 15 and 18 additional samples from four of these subjects were obtained over a period of 2 months. Samples from individuals (n=1043) who visited the University Health Network for a routine check-up were collected to study the association between KLK6 with age and gender. Samples from patients with renal failure (n=106) were also obtained and KLK6 and creatinine concentrations were analyzed by ELISA and an automated enzymatic method, respectively.The reference interval was established to be 1.04–3.93 ng/mL. The index of individuality was 0.43 and the reference change value was 35%. Only two serum samples would be required to estimate the homeostatic setting point of an individual. There is a weak but highly significant positive correlation between KLK6 and age (p<0.0001). Furthermore, there is a significant positive correlation between serum concentrations of KLK6 and creatinine (p<0.0001), in patients with renal failure.The established reference interval for KLK6 and the estimation of its biological variation will further aid in the clinical use of this protein as a serum marker of malignancy and other diseases.

scholarly journals Biological Variation of Vitamins in Blood of Healthy Individuals

2005 ◽  
Vol 51 (11) ◽  
pp. 2145-2150 ◽  
Author(s):  
Dinesh K Talwar ◽  
Mohammed K Azharuddin ◽  
Cathy Williamson ◽  
Yee Ping Teoh ◽  
Donald C McMillan ◽  
...  
Keyword(s):  
Whole Blood ◽  
Total Error ◽  
Reference Intervals ◽  
Biological Variation ◽  
Reference Change Value ◽  
Objective Quality ◽  
Variation Data ◽  
Quality Specifications ◽  
Index Of Individuality ◽  
Apparently Healthy

Abstract Background: Components of biological variation can be used to define objective quality specifications (imprecision, bias, and total error), to assess the usefulness of reference values [index of individuality (II)], and to evaluate significance of changes in serial results from an individual [reference change value (RCV)]. However, biological variation data on vitamins in blood are limited. The aims of the present study were to determine the intra- and interindividual biological variation of vitamins A, E, B1, B2, B6, C, and K and carotenoids in plasma, whole blood, or erythrocytes from apparently healthy persons and to define quality specifications for vitamin measurements based on their biology. Methods: Fasting plasma, whole blood, and erythrocytes were collected from 14 healthy volunteers at regular weekly intervals over 22 weeks. Vitamins were measured by HPLC. From the data generated, the intra- (CVI) and interindividual (CVG) biological CVs were estimated for each vitamin. Derived quality specifications, II, and RCV were calculated from CVI and CVG. Results: CVI was 4.8%–38% and CVG was 10%–65% for the vitamins measured. The CVIs for vitamins A, E, B1, and B2 were lower (4.8%–7.6%) than for the other vitamins in blood. For all vitamins, CVG was higher than CVI, with II &lt;1.0 (range, 0.36–0.95). The RCVs for vitamins were high (15.8%–108%). Apart from vitamins A, B1, and erythrocyte B2, the imprecision of our methods for measurement of vitamins in blood was within the desirable goal. Conclusions: For most vitamin measurements in plasma, whole blood, or erythrocytes, the desirable imprecision goals based on biological variation are obtainable by current methodologies. Population reference intervals for vitamins are of limited value in demonstrating deficiency or excess.

Within-subject and between-subject biological variation of first morning void urine amino acids in 12 healthy subjects

2020 ◽  
Vol 58 (11) ◽  
pp. 1901-1909
Author(s):  
Hamit Hakan Alp ◽  
Halil İbrahim Akbay ◽  
Erdem Çokluk ◽  
Zubeyir Huyut ◽  
Sıddık Keskin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Healthy Subjects ◽  
Total Error ◽  
Reference Intervals ◽  
Biological Variation ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Variance Homogeneity

AbstractBackgroundUrine amino acid analysis is used for the assessment of various diseases. The aim of this study was to estimate the valid biological variation (BV) components (within- and between-subjects) required for the safe clinical application of free urine amino acids.MethodsFirst morning void urine samples were taken from 12 healthy subjects (five females, seven males) once a week for 10 consecutive weeks, and amino acid analysis was performed using an Agilent 6470 triple quadrupole tandem mass spectrometer instrument. The obtained data were subjected to normality, outlier and variance homogeneity analyses prior to coefficient of variation (CV) analysis. Within- and between-subject BV values (CVI and CVG) of 39 amino acids were determined for all subjects. In addition, the index of individuality (II), reference change value (RCV), imprecision, bias and total error were estimated using BV data obtained from our study.ResultsThe CVI values ranged from 8.9 (histidine) to 36.8% (trans-4-hydroxyprolin), while the CVG values ranged from 25.0 (1-methyl-L-histidine) to 63.3% (phenylalanine). The II value of most amino acids was less than 0.6 and ranged between 0.21 and 0.88. The imprecision, bias and total error ranged between 4.45 and 16.6, between 7.69 and 16.6, and between 18.4 and 43.2, respectively.ConclusionsThis study, designed according to a rigorous protocol, has the feature of being the first to give information about BV data of urine amino acids. We believe that the reference intervals have a limitation in the evaluation of consecutive results from an individual, so the use of RCV would be more appropriate.

Biological variation of intact fibroblast growth factor 23 measured on a fully automated chemiluminescent platform

2019 ◽  
Vol 56 (3) ◽  
pp. 381-386 ◽  
Author(s):  
Antonín Jabor ◽  
Zdenek Kubíček ◽  
Jitka Komrsková ◽  
Tereza Vacková ◽  
Jiří Vymětalík ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Biological Variation ◽  
Fibroblast Growth ◽  
Vitamin D Metabolism ◽  
Automated Assay ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Non Gaussian

Background Fibroblast growth factor 23 (FGF23), a potent regulator of phosphate and vitamin D metabolism, is a new biomarker of kidney, bone and cardiovascular disorders. The aim of this study was to assess the biological variation of intact fibroblast growth factor 23 (iFGF23). Methods The within-subject (CVI) and between-subject (CVG) biological variations were assessed in 14 healthy volunteers in a six-week protocol (seven samples). Imprecision (CVA) was assessed by duplicate measurements and the EP15-A2 protocol. Intact FGF23 was measured using a fully automated chemiluminescent assay (Liaison XL, DiaSorin S.p.A., Saluggia, Italy). Two methods with different sensitivities to non-Gaussian distribution were used to estimate the CVI, SD ANOVA and CV ANOVA methods. We calculated the index of individuality (II) and reference change values. Results Depending on the statistical method used, the CVI and CVA were 14.2 and 3.7% (SD ANOVA) or 12.5 and 3.9% (CV ANOVA), respectively. The corresponding reference change values were 40.5 and 36.4%, respectively. The CVG was 13.4% (SD ANOVA was the only option), and the total imprecision (EP15-A2) was less than 7%. Conclusions The measurement of iFGF23 demonstrated a CVA less than 4% during the experimental estimation of biological variation. The total imprecision was less than 7% in the EP15-A2 experiment. The CVI values of iFGF23 in healthy persons were 14.2 (SD ANOVA) and 12.5% (CV ANOVA), respectively. The CVG was 13.4%, and the resulting index of individuality was 1.06. The reference change value was less than 41%. The availability of this automated assay for iFGF23 with well-characterized biological variation data delivers opportunities for improved availability and application of this assay clinically.

Calculation of Biological Variation Components and Reference Change Value for Serum Copper and Zinc

2019 ◽  
Vol 65 (06/2019) ◽  
Author(s):  
Çiğdem Yücel ◽  
Müjgan Ercan ◽  
Turan Turhan ◽  
Ahmet Esendemir ◽  
Mesude Falay ◽  
...  
Keyword(s):  
Serum Copper ◽  
Biological Variation ◽  
Copper And Zinc ◽  
Reference Change Value

A study of biological and lifestyle factors, including within-subject variation, affecting concentrations of growth differentiation factor 15 in serum

2019 ◽  
Vol 57 (7) ◽  
pp. 1035-1043 ◽  
Author(s):  
Magdalena Krintus ◽  
Federica Braga ◽  
Marek Kozinski ◽  
Simona Borille ◽  
Jacek Kubica ◽  
...  
Keyword(s):  
Smoking Status ◽  
Adult Population ◽  
Lifestyle Factors ◽  
Biological Variation ◽  
Healthy Population ◽  
Intraindividual Variation ◽  
Growth Differentiation Factor 15 ◽  
Differentiation Factor ◽  
Reference Change Value ◽  
Age Related

Abstract Background Growth differentiation factor 15 (GDF-15) is an emerging cardiovascular biomarker, and a fully automated immunoassay has recently become available. The objectives of the study were to identify biological and lifestyle factors affecting serum GDF-15 concentrations and derive robust reference intervals, and to estimate GDF-15 within-subject biological variation and derived indices. Methods A presumably healthy population of 533 questionnaire-screened adults was used to identify the biological and lifestyle determinants of serum GDF-15. Following stringent exclusion criteria, a final group of 173 individuals was selected to establish GDF-15 reference interval. Twenty-six healthy volunteers were enrolled in the biological variation substudy. Results Using a multiple regression model, age, B-type natriuretic peptide and C-reactive protein as well as smoking status were significantly related to serum GDF-15 concentrations. The upper reference limit (URL) for serum GDF-15 concentrations (90% confidence interval [CI]) was 866 ng/L (733–999 ng/L), with no sex-related difference. Although GDF-15 tended to increase with age, the weak dependence of marker from age does not justify age-related URL. The within-subject CV was 6.3% (95% CI, 4.5%–8.5%), with no sex difference in intraindividual variances. The reference change value (RCV) for GDF-15 was 23%, and two are the specimens required to ensure that the mean GDF-15 result is within ±10% of the individual’s homeostatic set point. Conclusions By identifying the main factors influencing serum GDF-15 concentrations, we robustly established the URL to be applied in adult population. As intraindividual variation of GDF-15 is relatively low, monitoring longitudinal changes in its concentrations over time using RCV can be a good alternative for interpreting GDF-15 in clinical setting.

Evaluation of biological variations in glucose and glycated hemoglobin levels in healthy individuals

2017 ◽  
Vol 43 (5) ◽  
pp. 495-501
Author(s):  
Cihan Coskun ◽  
Berrin Bercik Inal ◽  
Humeyra Ozturk Emre ◽  
Sehide Baz ◽  
Alper Gumus ◽  
...  
Keyword(s):  
International Organizations ◽  
Glycated Hemoglobin ◽  
Reference Interval ◽  
Reference Intervals ◽  
Study Group ◽  
Test Results ◽  
Healthy Individuals ◽  
Reference Change Value ◽  
Performance Specifications ◽  
Index Of Individuality

Abstract Objective: In this study, we firstly aimed to determine components of biological variations (BVCs) in levels of glucose and glycated hemoglobin (HbA1c) in detail based on guidance from relevant organizations and experts. We also investigated whether reference intervals for both analytes were useful for evaluations, particularly consecutive test results. Methods: The study group consisted of 36 healthy volunteers. Samples were collected from each individual 4 times every 2 weeks for 45 days. All samples were assayed in duplicate within a single run. Finally, we estimated BVCs and the analytical performance specifications of both analytes. Results: Our results were fairly compatible with current biological variations (BVs) in both analytes reported in a database. It was calculated as within biological variation (CVI)=4.2% and between-subject variation (CVG)=5.3% for glucose while calculating as CVI=1.7% and CVG=4.5% for HbA1c. According to these results, the index of individuality (II) of glucose was higher than 0.6 while HbA1c’s II was lower than this value. Conclusion: We thought that guidelines from relevant international organizations should be followed to standardize the study design and to appropriately calculate BVCs for any analyte in BV studies. Finally, reference change value should be used to evaluate meaningful differences in HbA1c levels instead of reference interval.

Biological variation of serum neurofilament light chain

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Claus Vinter Bødker Hviid ◽  
Anne Tranberg Madsen ◽  
Anne Winther-Larsen
Keyword(s):  
Light Chain ◽  
Reference Intervals ◽  
Biological Variation ◽  
Healthy Individuals ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Linear Mixed Effects ◽  
Serial Measurements ◽  
Analytical Variation ◽  
Apparently Healthy

Abstract Objectives The neurofilament light chain (NfL) has emerged as a versatile biomarker for CNS-diseases and is approaching clinical use. The observed changes in NfL levels are frequently of limited magnitude and in order to make clinical decisions based on NfL measurements, it is essential that biological variation is not confused with clinically relevant changes. The present study was designed to evaluate the biological variation of serum NfL. Methods Apparently healthy individuals (n=33) were submitted to blood draws for three days in a row. On the second day, blood draws were performed every third hour for 12 h. NfL was quantified in serum using the Simoa™ HD-1 platform. The within-subject variation (CVI) and between-subject variation (CVG) were calculated using linear mixed-effects models. Results The overall median value of NfL was 6.3 pg/mL (range 2.1–19.1). The CVI was 3.1% and the CVG was 35.6%. An increase in two serial measurements had to exceed 24.3% to be classified as significant at the 95% confidence level. Serum NfL levels remained stable during the day (p=0.40), whereas a minute variation (6.0–6.6 pg/mL) was observed from day-to-day (p=0.02). Conclusions Serum NfL is subject to tight homeostatic regulation with none or neglectable semidiurnal and day-to-day variation, but considerable between-subject variation exists. This emphasizes serum NfL as a well-suited biomarker for disease monitoring, but warrants caution when interpreting NfL levels in relation to reference intervals in a diagnosis setting. Furthermore, NfL’s tight regulation requires that the analytical variation is kept at a minimum.

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