Biological variation of glycated albumin, glucose and albumin in healthy Turkish subjects

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Osman Oğuz ◽  
Hilal Mercan ◽  
F. Sinem Hocaoglu-Emre
Keyword(s):  
Coefficient Of Variation ◽  
Glycated Albumin ◽  
Biological Variation ◽  
Test Results ◽  
Routine Test ◽  
Short Term ◽  
Standardized Protocol ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Term Monitoring

AbstractObjectivesBiological variation (BV) in laboratory tests can be defined as the variation in analyte concentration over time within and between individuals. Glycated albumin (GA) is a ketoamine which is used in the short-term monitoring of diabetes. The aim of this research was to determine BV of GA, glucose, and albumin under a well-designed and standardized protocol.MethodsBlood samples were collected weekly from 21 healthy subjects (10 males, 11 females) for four consecutive weeks. Samples were analyzed using enzymatic methods in duplicate. After subjected to outlier and normality tests, variables as the within-subject biologic coefficient of variation (CVI) and between-subject biologic coefficient of variation (CVG), the index of individuality (II), and reference change value (RCV) were calculated.ResultsAnalytical coefficient of variation (CVA) was 3.5, 1.78, and 2.9%, for GA, glucose and albumin, respectively. The estimates for CVI and CVG: GA: 4.1%, 6.3%; glucose: 3.8%, 4.8%; albumin: 3.5%, 4%. RCVs and IIs were: 15%, 0.60; 12%, 0.79; 13%, 0.9 for GA, glucose and albumin, respectively.ConclusionsThe BV data of GA derived from this study might be applied to understand routine test results better and establish the quality standards for the analyte.

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.

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.

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.

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.

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 in serum bone turnover markers

2020 ◽  
Vol 57 (2) ◽  
pp. 144-150
Author(s):  
Shuo Wang ◽  
Runqing Mu ◽  
Xin Zhang ◽  
Ke Yun ◽  
Hong Shang ◽  
...  
Keyword(s):  
Bone Turnover ◽  
Clinical Application ◽  
Bone Turnover Markers ◽  
Type I Collagen ◽  
Biological Variation ◽  
Type I ◽  
Total N ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Turnover Markers

Background Serum total N-terminal propeptide of type I collagen (P1NP) and serum C-terminal telopeptide of type I collagen (CTX) are used as reference analytes of bone turnover in clinical application. Biological variation is important for clinical application of these biomarkers. However, the biological variation data of these biomarkers are not consistent. The present study determined biological variations of total P1NP and CTX and their confidence intervals in China using electrochemiluminescence. Methods We collected samples from 25 healthy individuals (17 women and 8 men, ranging from 22 to 49 years of age) at weekly intervals for six weeks. Samples were analysed in a single run in duplicate. Biological variations and their related parameters, such as reference change value and index of individuality (II) were calculated. The results were compared with individual studies in the EFLM database. Results Within-subject and between-subject biological variations were 8.0% and 32.5% for total P1NP and 11.4% and 38.7% for CTX, respectively. The index of individuality for total P1NP and CTX was 0.25 and 0.30, while the reference change value for P1NP values and CTX was 22.4% and 31.9%, respectively. Conclusions No difference was found in weekly biological variation of bone turnover markers between men and premenopausal women. Compared with daily and monthly variation, the present study based on weekly variation provided additional support for clinical application.

scholarly journals Performance goals for immunoglobulins and serum free light chain measurements in plasma cell dyscrasias can be based on biological variation

2016 ◽  
Vol 54 (6) ◽  
Author(s):  
Charlotte Toftmann Hansen
Keyword(s):  
Plasma Cell ◽  
Performance Standards ◽  
The Elderly ◽  
Biological Variation ◽  
Plasma Cell Dyscrasia ◽  
Serum Free ◽  
Serum Free Light Chain ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Plasma Cell Dyscrasias

AbstractMeasurements of immunoglobulins and serum free light chains (sFLC) are frequently used in patients with monoclonal plasma cell dyscrasia (PCD). For optimum patient care, well-defined performance standards or goals for the measured concentrations of immunoglobulins and sFLC are required. Generally, data based on biological variation is a good and reliable method for setting desirable performance standards; this also applies for the measurements of paraprotein and sFLC. The benefits of this approach are several. Among others, it is independent of the clinician, and it provides us with information about reference change value and index of individuality. Several studies on biological variation of both immunoglobulins and sFLC have been published, and mostly the studies are well performed. The studies normally show small within-subject biological variation resulting in strict analytical goals, which in most cases are difficult to meet. Nevertheless, we still need further information on biological variation of immunoglobulins and sFLC in patients with PCD and in the elderly, which are the main target populations for the two measurands. Furthermore, to improve data on biological variation of immunoglobulins and sFLC, studies accounting for number of individuals, samples, and replicates, as well as time length of the studies are needed.

scholarly journals Estimation and Application of Biological Variation of Urinary δ-Aminolevulinic Acid and Porphobilinogen in Healthy Individuals and in Patients with Acute Intermittent Porphyria

2006 ◽  
Vol 52 (4) ◽  
pp. 650-656 ◽  
Author(s):  
Aasne K Aarsand ◽  
Per Hyltoft Petersen ◽  
Sverre Sandberg
Keyword(s):  
Aminolevulinic Acid ◽  
Acute Intermittent Porphyria ◽  
Fold Increase ◽  
Biological Variation ◽  
Test Results ◽  
Healthy Individuals ◽  
Short Term ◽  
Real Change ◽  
Previous Sample

Abstract Background: Diagnosis of an attack of acute intermittent porphyria (AIP) is based on the demonstration of increased concentrations of porphobilinogen (PBG) and δ-aminolevulinic acid (ALA) in urine, but many AIP patients also have high baseline concentrations in remission. The aim of this study was to estimate the biological variations of ALA, PBG, and porphyrins in healthy individuals and AIP patients to improve interpretation of test results. Methods: Fifteen healthy individuals and 15 AIP patients were included, and biological variations were calculated based on urine samples collected weekly for 10 consecutive weeks. For the AIP patients, long-term variations were also estimated based on 7 samples collected through a 2-year period. Results: The porphyrin variances were inhomogeneously distributed; biological variations of porphyrins were therefore not calculated. The within-subject biological variations of ALA and PBG were 16%–20% in the short-term settings and for PBG, 25% in the long-term setting, giving reference change values of ∼50% and 70%, respectively. The probability of detecting a 100% real change in PBG was 97% in the short-term setting and 80% in the long-term setting. Conclusions: In an AIP patient, a 2-fold increase in PBG, independent of the baseline concentration, will be detected with a probability &gt;80% and is most likely related to the patient’s disease and not caused only by analytical and biological variation. When PBG is used in the assessment of AIP-related symptoms, both the PBG concentration in remission and the length of time since the previous sample must be considered.

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