Analytical quality specifications for common reference intervals

2004 ◽  
Vol 42 (7) ◽  
Author(s):  
Carmen Ricós ◽  
Maria Vicenta Doménech ◽  
Carmen Perich
Keyword(s):  
Real Life ◽  
Reference Interval ◽  
Population Based ◽  
Reference Intervals ◽  
Healthy Population ◽  
Analytical Quality ◽  
Related Factors ◽  
Cross Sectional ◽  
Reference Change Value ◽  
Quality Specifications

AbstractInterpretation oflaboratory test results requires comparison to some type of reference value or reference interval. These comparisons can be cross-sectional (population-based reference interval and cut-off values) or longitudinal (reference change value). Quality specifications for cross-sectional comparison have been established by determining the influence of analytical bias and imprecision on the percentage ofthe healthy population falling outside the reference limits, when sharing population-based reference intervals in a Gaussian distribution ofresults. Quality specifications for longitudinal comparisons are equally important and are often overlooked, since less work has been done in this area. Some criteria suggest that a difference between consecutive results designates a true change in a patient health status when the difference is higher than the within-subject biological variation plus the within-laboratory analytical variation. In this chapter we discuss the clinical considerations and laboratory-related factors that must be considered when quality specifications are applied to sharing reference comparisons. Real life experience shows that different analytical methods can produce comparable results when common quality goals are established, and quality can be achieved through a willingness to work together. Within the existing organization, the current specifications for analytical quality and a dedication to quality health care makes it possible to achieve transferability between laboratories within a geographic area.

scholarly journals Establishment of Hematological Reference intervals for healthy Children in Elobied City, Sudan

2021 ◽  
Vol 2 (4) ◽  
pp. 24-31
Author(s):  
Tarig Osman Khalafallah Ahmed ◽  
Malaz Elfatih Abd-elkareem Ahmed ◽  
Ream Elzain Abdelgadir ◽  
Hiba Awadelkareem Osman Fadl ◽  
Assad MA. Babker
Keyword(s):  
Blood Cells ◽  
Hematological Parameters ◽  
Venous Blood ◽  
White Blood Cells ◽  
Reference Interval ◽  
Cross Sectional Study ◽  
Reference Intervals ◽  
Healthy Population ◽  
Healthy Children ◽  
Cross Sectional

Hemogram Reference intervals are established since a healthy population is critical to accurately interpret laboratory tests, which include Hemoglobin estimation, Red blood cells count and indices, White blood cells count and differential in addition to Platelets count. This study aims to establish the reference interval of the complete hemogram amongst healthy Sudanese children in Elobied city, Sudan. A descriptive cross-sectional study  included 354 healthy children, aged between 3 to 17 years, who were categorized into three groups according to age. A questionnaire was fulfilled, EDTA anti-coagulated venous blood sample was collected from each child then the complete hemogram was performed automated hematological analyzer (Sysmex Xp 300), Finally, Data was analyzed by a software program (SPSS version 21). The hematological reference intervals for healthy children [Hb g/dl, HCT%, RBCs count x106μL, MCV/fL ,MCH /pg., MCHC g/dl ,WBCs count x10³/μL, Neutrophil count%, Eosinophil count %, Basophile count %, lymphocyte count ,Monocytes count%, RDW CV and PLTs count×10³/μL] are [(12.4±1.2),(37±4),(5.0 ±0.4), (82±5.0), (26±3.0), (32±3.0) ,(7.0±2.0) (47±10), (1±0.1) ,(0±0),(45± 10),(7 ± 4), (13±1.8) &(227±91)] respectively. The hematological RI for healthy children in Elobied was established in this study to be representative of this population, there was a significant gender-based difference in all the evaluated hematological parameters, they were found to be higher in males than in females except for basophil (%). Finally, the results of this study would shed a light on the importance of establishing RI for the children population in Elobied.

scholarly journals Chitinase-3-like protein 1: reference interval of a healthy population and its diagnostic value for liver fibrosis in Pakistan

BioMedica ◽  
2021 ◽  
Vol 37 (3) ◽  
pp. 1-13
Author(s):  
Faryal Husnain ◽  
Muhammad Dilawar Khan ◽  
Omar Rasheed Chughtai ◽  
Akhtar Rasheed Chughtai ◽  
Shakeel Ashraf ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Fibrosis ◽  
Reference Interval ◽  
Diagnostic Value ◽  
Reference Intervals ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Population ◽  
International Studies ◽  
Cross Sectional ◽  
Pakistani Population

<p><strong>Background and Objective:</strong> Chitinase-3-like protein 1 (CHI3L1) is an upcoming biomarker for the diagnosis of liver fibrosis. The reference intervals (RIs) for CHI3L1 have not been established in the Pakistani population. Thus, this study aimed to determine the RIs in our population and the cut-off value for diagnosis of hepatic fibrosis.</p> <p><strong>Methods:</strong> This is a cross-sectional study. A total of 408 participants (202 healthy and 206 diagnosed liver fibrosis cases) were recruited. Serum CHI3L1 level was measured on CHI3L1 kits (Proprium Biotech Co. Ltd) by manual enzyme-linked immunosorbent assay. The RIs were estimated by percentile and working normal method.</p> <p><strong>Results:</strong> The distribution of CHI3L1 values showed no remarkable variation with gender and age. The 95% RI of CHI3L1 was 12.80-81.80 ng/ ml in healthy Pakistani subjects and the cut-off for the diagnosis was 102.12 ng/ml in hepatic fibrosis cases.</p> <p><strong>Conclusion:</strong> The RIs in healthy adults and the cut-off for the diagnosis of hepatic fibrosis of serum CHI3L1 were determined in a selective adult Pakistani population. This will be a useful reference for further local and international studies.</p>

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.

Distribution of HOMA-IR in a population-based cohort and proposal for reference intervals

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bassel Matli ◽  
Andreas Schulz ◽  
Thomas Koeck ◽  
Tanja Falter ◽  
Johannes Lotz ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fasting Glucose ◽  
Reference Group ◽  
Reference Interval ◽  
Population Based ◽  
Reference Intervals ◽  
Health Study ◽  
Specific Reference ◽  
Model Assessment ◽  
Significant Difference

Abstract Objectives Insulin resistance (IR) is a hallmark of type 2 diabetes mellitus (DM). The homeostatic model assessment of insulin resistance (HOMA-IR) provides an estimate for IR from fasting glucose and insulin serum concentrations. The aim of this study was to obtain a reference interval for HOMA-IR for a specific insulin immunoassay. Methods The Gutenberg Health Study (GHS) is a population-based, prospective, single-center cohort study in Germany with 15,030 participants aged 35–74 years. Fasting glucose, insulin, and C-peptide were available in 10,340 participants. HOMA-IR was calculated in this group and three reference subgroups with increasingly more stringent inclusion criteria. Age- and sex-dependent distributions of HOMA-IR and reference intervals were obtained. In a substudy three insulin assays were compared and HOMA-IR estimated for each assay. Results Among the 10,340 participants analyzed there were 6,590 non-diabetic, 2,901 prediabetic, and 849 diabetic individuals. Median (interquartile range [IQR]) HOMA-IR was 1.54 (1.13/2.19), 2.00 (1.39/2.99), and 4.00 (2.52/6.51), respectively. The most stringently selected reference group consisted of 1,065 persons. Median (IQR) HOMA-IR was 1.09 (0.85/1.42) with no significant difference between men and women. The 97.5th percentile was 2.35. There was a non-significant trend towards higher values with older age. Comparison of three immunoassays for insulin showed an unsatisfactory correlation among the assays and systematic differences in calculated HOMA-IR. Conclusions We present HOMA-IR reference intervals for adults derived by more or less stringent selection criteria for the reference cohort. In addition we show that assay specific reference intervals for HOMA-IR are required.

scholarly journals Self‐reported visual difficulties in Europe and related factors: a European population‐based cross‐sectional survey

2020 ◽  
Author(s):  
Nicolas Leveziel ◽  
Simon Marillet ◽  
Tasanee Braithwaite ◽  
Tunde Peto ◽  
Pierre Ingrand ◽  
...  
Keyword(s):  
Population Based ◽  
European Population ◽  
Cross Sectional Survey ◽  
Related Factors ◽  
Cross Sectional

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.

Analytical performance, reference values and decision limits. A need to differentiate between reference intervals and decision limits and to define analytical quality specifications

2012 ◽  
Vol 50 (5) ◽  
Author(s):  
Per Hyltoft Petersen ◽  
Esther A. Jensen ◽  
Ivan Brandslund
Keyword(s):  
Reference Values ◽  
Clinical Guidelines ◽  
Reference Intervals ◽  
Analytical Performance ◽  
International Expert ◽  
Analytical Quality ◽  
Quality Specifications ◽  
Reference Samples ◽  
Critical Situations

AbstractWith the increasing use of decision limits (action limits, cut-off points) specified for a number of analytical components in diagnosis and for action in critical situations, formulated in national or international recommendations, the traditional interpretation of reference intervals has been uncertain, and sometimes the two concepts are being mixed up by incorporating risk calculations in the reference intervals. There is, therefore, a need to clarify the two concepts and to keep them definitely separated. Reference intervals are the 95% limits for the descriptions of the distributions of the values of analytical components measured on reference samples from reference individuals. Decision limits are based on guidelines from national and international expert groups defining specific concentrations of certain components as limits for decision about diagnosis or well-defined specific actions. Analytical quality specifications for reference intervals have been defined for bias since the 1990s, but in the recommendations specified in the clinical guidelines analytical quality specifications are only scarcely defined. The demands for negligible biases are, however, even more essential for decision limits, as the choice is no longer left to the clinician, but emerge directly from the concentration. Even a small bias will change the number of diseased individuals, so the demands for negligible biases are obvious. A view over the analytical quality as published gives a variable picture of bias for many components, but with many examples of considerable bias which must be critical – yet no specifications have been stipulated until now.

scholarly journals The Nordic diet and cognition – The DR's EXTRA Study

2015 ◽  
Vol 114 (2) ◽  
pp. 231-239 ◽  
Author(s):  
Reija Männikkö ◽  
Pirjo Komulainen ◽  
Ursula Schwab ◽  
Harri M. Heikkilä ◽  
Kai Savonen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Positive Association ◽  
Word List ◽  
Population Based ◽  
Lifestyle Factor ◽  
Related Factors ◽  
Cross Sectional ◽  
Nordic Diet ◽  
Diet Score

The rapid increase in the prevalence of dementia associated with ageing populations has stimulated interest in identifying modifiable lifestyle factors that could prevent cognitive impairment. One such potential preventive lifestyle factor is the Nordic diet that has been shown to reduce the risk of CVD; however, its effect on cognition has not been studied. The aim of the present study was to estimate the cross-sectional and longitudinal associations of the baseline Nordic diet with cognitive function at baseline and after a 4-year follow-up in a population-based random sample (n1140 women and men, age 57–78 years) as secondary analyses of the Finnish Dose-Responses to Exercise Training study. The Nordic diet score was created based on reported dietary components in 4-d food records. Cognition was assessed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery and the Mini-mental State Examination (MMSE). The baseline Nordic diet score had been positively associated with Verbal Fluency (β 0·08 (95 % CI 0·00, 0·16),P= 0·039) and Word List Learning (β 0·06 (95 % CI 0·01, 0·10),P= 0·022) at 4 years but not with the Consortium to Establish a Registry for Alzheimer's Disease total score (CERAD-TS) or MMSE at 4 years, after adjustment for baseline cognitive scores, demographic factors and health-related factors. After excluding individuals with impaired cognition at baseline, the baseline Nordic diet score had also been positively associated with the CERAD-TS (β 0·10 (95 % CI 0·00, 0·20),P= 0·042) and MMSE (β 0·03 (95 % CI 0·00, 0·06),P= 0·039) at 4 years. These associations disappeared after further adjustment for energy intake. In conclusion, the Nordic diet might have a positive association with cognition in individuals with normal cognition.

scholarly journals Metabolic Syndrome and Its Related Factors among Hospital Employees: A Population-Based Cohort Study

2021 ◽  
Vol 18 (18) ◽  
pp. 9826
Author(s):  
Yi-Syuan Wu ◽  
Wen-Chii Tzeng ◽  
Chi-Ming Chu ◽  
Wei-Yun Wang
Keyword(s):  
Metabolic Syndrome ◽  
At Risk ◽  
Health Management ◽  
Statistical Significance ◽  
Population Based ◽  
Health Management Information System ◽  
Related Factors ◽  
Cross Sectional ◽  
Longitudinal Cohort ◽  
Hospital Employees

Several studies have reported on metabolic syndrome (MetS) based on cross-sectional designs, which cannot show a long-term result. Information is lacking on MetS and related factors based on a longitudinal cohort. This study aimed to examine the relationship between MetS and related factors for a total of six years among hospital employees. A population-based study was conducted, including 746 staff. A total of 680 staff without MetS in 2012 were enrolled in the analysis for repeated measurement of six years of the longitudinal cohort. Data were retrieved from the hospital’s Health Management Information System. Analyses were performed using Student’s t-test, chi-square test, logistic regression, and generalised estimating equations. Statistical significance was defined as p < 0.05. Hospital employees aged between 31 and 40 (odds ratio (OR) = 4.596, p = 0.009), aged between 41 and 50 (OR = 7.866, p = 0.001), aged greater than 50 (OR = 10.312, p < 0.001), with a body mass index (BMI) of 25.0~29.9 kg/m2 (OR = 3.934, p < 0.001), a BMI ≥ 30 kg/m2 (OR = 13.197, p < 0.001), higher level of white blood counts (β = 0.177, p = 0.001), alanine aminotransferase (β = 0.013, p = 0.002), and uric acid (β = 0.223, p = 0.005) were at risk of being diagnosed with MetS. The identification of at-risk hospital employees and disease management programs addressing MetS-related factors are of great importance in hospital-based interventions.

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