Feasibility of centralized measurements of glycated hemoglobin in the Diabetes Control and Complications Trial: a multicenter study. The DCCT Research Group.

1987 ◽  
Vol 33 (12) ◽  
pp. 2267-2271 ◽  
Keyword(s):  
Quality Control ◽  
High Performance ◽  
Glycated Hemoglobin ◽  
Multicenter Trial ◽  
Diabetes Control ◽  
Mean Values ◽  
Hb A1c ◽  
Control Procedures ◽  
Over Time

Abstract A method for measuring glycated hemoglobin (Hb A1c) and an accompanying method of specimen transport to a central laboratory were developed for the multicenter Diabetes Control and Complications Trial (DCCT). In the DCCT, results for Hb A1c are used to assess chronic glycemic control for data collection and patient management. During the feasibility phase of the trial, central (CHL) and backup laboratories using automated, "high-performance" ion-exchange liquid-chromatographic methods were established. Whole-blood samples were stored (4 degrees C) at each of the 21 clinical centers for up to 72 h before air-express shipment to the CHL. Quality-control procedures included daily analyses of three calibration specimens. A pooled hemolysate was assayed frequently over time as a long-term quality control (LTQC). After 18 months, within- and between-run CVs were less than 6%. Mean values for split duplicate samples assayed in a masked fashion at the CHL were nearly identical. LTQC results indicated no significant assay drift over time. More than 6000 samples were assayed (mean interval between obtaining the blood sample and completing the assay: less than six days). Hb A1c evidently can be precisely and reliably measured in the context of a long-term, multicenter trial such as the DCCT.

scholarly journals Long-term quality assessment and monitoring of light microscope performance through accessible and reliable protocols, tools and metrics

2021 ◽  
Author(s):  
Orestis Faklaris ◽  
Leslie Bancel-Vallee ◽  
Aurelien Dauphin ◽  
Baptiste Monterroso ◽  
Perrine Frere ◽  
...  
Keyword(s):  
Quality Control ◽  
Data Processing ◽  
Light Microscope ◽  
Wide Field ◽  
Experimental Limit ◽  
Limit Values ◽  
Power Monitoring ◽  
Control Procedures ◽  
Over Time

Reliable, reproducible and comparable results are what biology requires from microscopy. To achieve that level of confidence, monitoring the stability of the microscope performance over time with standardized quality testing routines is essential for mining quantitative data. Three levels of microscope quality control procedures should be considered: i) usage of accessible and affordable tools and samples, ii) execution of easy and fast, preferably automatized, acquisition protocols, iii) analysis of data in the most automated way possible with adequate metrics for long-term monitoring. In this paper, we test the acquisition protocols on the mainly used microscope techniques (wide-field, spinning disk and confocal microscopy) with simple quality control tools. Seven protocols specify metrics on measuring the lateral and axial resolution (Point-Spread Function) of the system, field flatness, chromatic aberrations and co-registration, illumination power monitoring and stability, stage drift and positioning repeatability and finally temporal and spatial noise sources of camera detectors. We designed an ImageJ/FiJi java plugin named MetroloJ_QC to incorporate the identified metrics and automatize the data processing for the analysis. After processing and comparing the data of microscopes from more than ten imaging facilities, we test the robustness of the metrics and the protocols by determining experimental limit values. Our results give a first extensive characterization of the quality control procedures of a light microscope, with an automated data processing and experimental limit values that can be used by core facility staff and researchers to monitor the microscope performance over time.

Long-Term Trends in Biochemical Data Obtained from Two Population Surveys

1986 ◽  
Vol 23 (4) ◽  
pp. 474-486 ◽  
Author(s):  
P M G Broughton ◽  
Roger Holder ◽  
Deborah Ashby
Keyword(s):  
Quality Control ◽  
Mean Value ◽  
Population Surveys ◽  
Men And Women ◽  
Mean Values ◽  
Epidemiological Surveys ◽  
Abrupt Changes ◽  
Control Procedures ◽  
Long Term Trends

A study has been made of the variations in monthly mean values of 10 serum constituents in subjects participating in two partly-concurrent long-term epidemiological surveys. Closely similar patterns of variation were found in men in both surveys and in men and women in one survey. During the 6 years of the study, four types of variation of the monthly mean concentrations were identified in varying combinations: (i) abrupt changes of less than 2% not detected by quality control procedures; (ii) a gradual drift in mean value; (iii) haphazard variations in mean values; and (iv) seasonal variations in bilirubin and urea, identical in men and women. The implications of these findings for the design of long-term epidemiological surveys, and the criteria for designating variations as seasonal, are discussed.

Glycated hemoglobin in fractionated erythrocytes.

1989 ◽  
Vol 35 (6) ◽  
pp. 958-962 ◽  
Author(s):  
K Nakashima ◽  
O Nishizaki ◽  
Y Andoh ◽  
H Takei ◽  
A Itai ◽  
...  
Keyword(s):  
Glycated Hemoglobin ◽  
Normal Subjects ◽  
Middle Aged ◽  
Glycemic Status ◽  
Hb A1c ◽  
Cell Age ◽  
Initial Stage ◽  
Treatment Of Diabetes ◽  
Term Monitoring

Abstract Erythrocytes were fractionated, by centrifugation, on the basis of cell density, which is proportional to cell age. Glycated hemoglobin (Hb A1c) in the fractionated cells was measured and compared with the Hb A1c in whole blood and with the fructosamine concentrations in plasma of normal and diabetic subjects. In normal subjects, Hb A1c increased according to the age of the erythrocytes, but hyperbolically rather than linearly, indicating the slow conversion of Hb A to Hb A1c with saturability. The greatest correlation of Hb A1c with plasma fructosamine was in younger middle-aged cells. A subgroup of subjects with impaired glucose tolerance had high Hb A1c in older cells. Hb A1c of the young cells reflects recent glycemic status, for monitoring the initial stage of the treatment of diabetics, whereas Hb A1c of the older middle-aged cells more specifically reflects the longer term glycemic status, for screening and for the long-term monitoring index for treatment of diabetes.

scholarly journals Long-Term Recreational Football Training and Health in Aging

2020 ◽  
Vol 17 (6) ◽  
pp. 2087
Author(s):  
Esther Imperlini ◽  
Annamaria Mancini ◽  
Stefania Orrù ◽  
Daniela Vitucci ◽  
Valeria Di Onofrio ◽  
...  
Keyword(s):  
Quality Control ◽  
Dna Repair ◽  
Successful Aging ◽  
Protein Quality ◽  
Metabolic Diseases ◽  
Control Mechanisms ◽  
Older Subjects ◽  
Football Training ◽  
Over Time

This narrative review aims to critically analyze the effects of exercise on health in aging. Here we discuss the main clinical and biomolecular modifications induced by long-term recreational football training in older subjects. In particular, the effects induced by long-term recreational football training on cardiovascular, metabolic and musculo-skeletal fitness, together with the modifications in the muscle expression of hallmarks related to oxidative metabolism, DNA repair and senescence suppression pathways and protein quality control mechanisms will be provided. All these topics will be debated also in terms of preventing non-communicable metabolic diseases, in order to achieve successful aging over time.

scholarly journals Implementation of Real-Time Quality Control Procedures by Means of a Probabilistic Estimate of Seawater Temperature and Its Temporal Evolution

2013 ◽  
Vol 30 (3) ◽  
pp. 609-625 ◽  
Author(s):  
Giuseppe M. R. Manzella ◽  
Marco Gambetta
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Position Control ◽  
Seawater Temperature ◽  
Likelihood Method ◽  
Temperature Profiles ◽  
Quality Of Data ◽  
Control Procedures ◽  
The Mediterranean

Abstract Near-real-time quality control procedures for temperature profiles collected from ships of opportunity were implemented during the 1980s in oceans across the world and from the 1990s in the Mediterranean. In this sea, the procedures were originally based on seven steps (detection of end of profile, gross range check, position control, elimination of spikes, Gaussian smoothing and resampling at 1-m intervals, general malfunction control, and comparison with climatology), complemented with initial and final visual checks. The quality of data derived from a comparison with historical data (namely, climatology) depends on the availability of a huge amount of data that can statistically represent the mean characteristics of the seawater. A significant amount of data has been collected, and the existing temperature database in the Mediterranean can now provide more information on temporal and spatial variability at monthly and mesoscales, and an improved procedure for data quality control has now been adopted. New “best” estimates of monthly temperature profiles are calculated by using a maximum likelihood method. It has been found that more than one “best estimate” temperature can be defined in particular areas and depths, as a consequence of climate variability. Additional near-real-time control procedures have been included in order to provide information on long-term variability associated with data. This information is included in metafiles to be used for reanalysis and studies on long-term variability and changes.

scholarly journals Relationship Of Glycated Haemoglobin (Hba1c) And Glucose In Streptozotocininduced Wistar Rats Is Determined By Linear Regression

2013 ◽  
Vol 3 (3) ◽  
pp. 1-5
Author(s):  
George Gborienemi Simeon ◽  
AA Uwakwe ◽  
GO Ibeh
Keyword(s):  
Diabetes Mellitus ◽  
Plasma Glucose ◽  
High Performance ◽  
Glycated Hemoglobin ◽  
Medical Science ◽  
Glycated Haemoglobin ◽  
Citrate Buffer ◽  
Liquid Chromatograph ◽  
Mean Values ◽  
Relationship Of

Objective To evaluate the relationship of glucose and glycated haemoglobin (HbA1C) in type 1 diabetes model induced by streptozotocin. Research Design and Methods Induction of diabetes mellitus was achieved through the intraperitoneal injection of 70mg/kg body weight of streptozotocin dissolved in 1m citrate buffer pH 4.5 twice daily for 2 days. A total number of thirty rats were used selected among those that have exceeded glucose threshold (>10.0mmol/l) 2 weeks after streptozotocin induction. All rats weighed between 240-300g. Samples for fasting plasma glucose and glycated haemoglobin were collected at the tail vein. Glucose was determined by the glucose oxidase method and HbA1C was determined by High Performance Liquid Chromatograph (HPLCEsi/ ms) with uv detection. Data was analysed by one way and two way analysis of variance using SPSS version. Results Significant linear relationship was demonstrated between plasma glucose level and glycated haemoglobin which could be predictive of risk of developing diabetes. Control samples had values within reference range, glucose (3.5-6.5 mmol/l) and glycated hemoglobin (4.3-7%). However diabetic test rats elicited values that varied significantly with time. Test result confirms the fact that higher mean values of plasma glucose in diabetic (positive) controls were due to the effect of streptozotocin. Conclusion Plasma glucose and glycated hemoglobin show positively mutual relationship and can be used in early diagnosis of diabetes mellitus. Using correlation coefficient and regression enhances measurement of the strength of the bivariate association and is predictive. Asian Journal of Medical Science, Volume-3 No-3 (2012), Page 1-5 DOI: http://dx.doi.org/10.3126/ajms.v3i3.4816

Long-term retrospective control procedures for monitoring analytical performance of laboratory instruments.

1984 ◽  
Vol 30 (1) ◽  
pp. 145-149 ◽  
Author(s):  
M L Gozzo ◽  
G Barbaresi ◽  
G Giocoli ◽  
B Zappacosta ◽  
C Zuppi
Keyword(s):  
Quality Control ◽  
Reliability Index ◽  
Total Error ◽  
Statistical Procedure ◽  
Analytical Performance ◽  
Clinical Usefulness ◽  
The Past ◽  
Analytical Results ◽  
Control Procedures

Abstract We propose a statistical procedure for long-term quality-control of laboratory instruments, including daily, day-to-day, and monthly evaluations. The procedure is based on the unique and unequivocal interpretation of five results for control sera by calculation of a Reliability Index and further manipulations of this unitless parameter. This method, which we have tested during the past two years, allows for monitoring analytical performance and making comparisons with results of interlaboratory surveys. The monthly analytical variability, expressed as "total error," is an indicator of the clinical usefulness of analytical results.

Glycated Hemoglobin Measurement: Comparison of Three Methods Versus High Performance Liquid Chromatography

2021 ◽  
pp. 193229682199717
Author(s):  
María Zulema Chaila ◽  
Matías Viniegra ◽  
Juan José Gagliardino ◽  
Alfredo Martínez ◽  
María Gabriela Simesen de Bielke ◽  
...  
Keyword(s):  
High Performance ◽  
Glycated Hemoglobin ◽  
Clinical Chemistry ◽  
Intraclass Correlation ◽  
Method Comparison ◽  
Control Program ◽  
International Federation ◽  
High Complexity ◽  
Quality Control Program ◽  
Mean Values

Background: HbA1c result provide information on metabolic control in diabetes mellitus (DM) and could also be used for its diagnosis. For its determination, the laboratory must be certified by the National Glycohemoglobin Standardization Program (NGSP) or the International Federation of Clinical Chemistry (IFCC) and comply with a strict quality control program. Aims: To determine the correlation and agreement between HbA1c results measured by three analytical methods (enzymatic, turbidimetric, and capillary electrophoresis) versus HPLC. Methods: Method comparison—1245 samples from equal number of subjects at 45 Association of High Complexity Laboratories (Asociación de Laboratorios de Alta Complejidad—ALAC) centers, centralizing sample processing and operator. Statistical analysis—analysis of variance (ANOVA) and nonparametric Friedman ANOVA test for related samples, means, and medians. Correlation and concordance—Pearson’s correlation and linear regression, intraclass correlation coefficient (Passing and Bablock and Bland and Altman). Results: The comparison of mean values obtained by the four methods showed statistically significant, but clinically irrelevant, differences: HbA1c by HPLC versus Electrophoresis 0.06% (0.42 mmol/mol) P = .000 (± 1.96 DS -0.070 -0.047), Enzymatic 0.087% (1 mmol/mol) P = .000 (± 1.96 DS 0.077 0.098), Turbidimetric 0.056% (0.38 mmol/mol) P = 0.000 (± 1.96 DS -0.067 -0.044). Their concordance showed intraclass correlation of single measures of 0.982 P < .001 (95% CI 0.987 - 0.9838). Conclusions: The three methods present low variability and high correlation versus the HPLC.

scholarly journals Antioxidant HPTLC-DPPH Fingerprinting of Honeys and Tracking of Antioxidant Constituents upon Thermal Exposure

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 357
Author(s):  
Md Khairul Islam ◽  
Tomislav Sostaric ◽  
Lee Yong Lim ◽  
Katherine Hammer ◽  
Cornelia Locher
Keyword(s):  
Antioxidant Activity ◽  
Quality Control ◽  
High Performance ◽  
Thermal Exposure ◽  
Bioactive Constituents ◽  
Potential Value ◽  
Novel Approach ◽  
Depth Study ◽  
Layer Chromatography ◽  
Over Time

The use of High-Performance Thin-Layer Chromatography (HPTLC) coupled with the use of DPPH* (2,2-diphenyl-1-picrylhydrazyl) as a derivatisation reagent is a novel approach to the analysis of antioxidant activity of honeys. The method facilitates the visualisation of individual constituents that contribute to the overall antioxidant activity of the honey, even if they are not yet chemically identified, and allows for the quantification of their antioxidant activity as gallic acid equivalents. The method supports a more in-depth study of the antioxidant activity of honey as it allows for a comparative analysis of the antioxidant fingerprints of honeys of different floral origin and is able to capture differences in their individual bioactive constituents. Further, it supports the tracking of changes in antioxidant activity of individual honey constituents over time upon exposure to different temperature conditions, which demonstrates the potential value of the method for in-process quality control.

scholarly journals Obese Nondiabetic Pregnancies and High Maternal Glycated Hemoglobin at Delivery as an Indicator of Offspring and Maternal Postpartum Risks: The Prospective PEACHES Mother-Child Cohort

2015 ◽  
Vol 61 (11) ◽  
pp. 1381-1390 ◽  
Author(s):  
Regina Ensenauer ◽  
Lena Brandlhuber ◽  
Maximiliane Burgmann ◽  
Christina Sobotzki ◽  
Carina Zwafink ◽  
...  
Keyword(s):  
Glycated Hemoglobin ◽  
International Association ◽  
Normal Weight ◽  
Cumulative Distribution ◽  
Large For Gestational Age ◽  
Distribution Analysis ◽  
Early Screening ◽  
C Peptide ◽  
Hb A1c

Abstract BACKGROUND We investigated whether obese pregnant women negative for gestational diabetes (GDM) still experience dysglycemia, as indicated by high glycated hemoglobin (Hb A1c) at delivery, and whether this impacts offspring and long-term maternal outcomes. METHODS Data of 462 mother-child pairs of our prospective Programming of Enhanced Adiposity Risk in Childhood – Early Screening (PEACHES) cohort study were analyzed. Of 885 obese and normal-weight pregnancies prospectively enrolled after GDM testing according to the International Association of Diabetes and Pregnancy Study Groups criteria, 462 GDM-negative mothers and their offspring were investigated. We assessed associations of maternal Hb A1c at delivery with large-for-gestational-age (LGA) birth weights, cord-blood C-peptide, and biomarkers of glucose metabolism and inflammation in obese mothers followed for 2.9 years (median) postpartum (n = 42). RESULTS Cumulative distribution analysis in GDM-negative normal-weight women (n = 155) revealed that 12% had Hb A1c ≥5.7% at delivery (high Hb A1c). Among obese GDM-negative women (n = 307), 31.9% (95% CI, 26.7%–37.4%) equaled or exceeded this cutoff. In obese GDM-negative women with Hb A1c ≥5.7% (n = 98) vs &lt;5.7% (n = 209) at delivery, newborns were more likely to be born LGA [adjusted odds ratio 3.56 (95% CI, 1.64–8.02)], and mean cordblood serum C-peptide was increased by 0.09 ng/mL (95% CI, 0.01–0.17 ng/mL). In the mothers at follow-up, mean postpartum Hb A1c, fasting glucose, high-sensitivity C-reactive protein, and fibrinogen concentrations were higher by 0.3% (95% CI, 0.1%–0.5%), 6.0 mg/dL (95% CI, 2.4–9.5 mg/dL), 6.8 mg/L (95% CI, 1.4–12.3 mg/L), and 74.9 mg/dL (95% CI, 13.6–136.2 mg/dL), respectively. CONCLUSIONS Increased Hb A1c in obese GDM-negative women at delivery indicates gestational dysglycemia, potentially conferring offspring and long-term maternal health risks. These findings should raise awareness as to careful monitoring of obese pregnancies. Measurement of Hb A1c at delivery could help select women who may need closer postpartum health checks.

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