Preparation and evaluation of laboratory quality control materials for the detection of IgG anti-A/B

2016 ◽  
Vol 40 (6) ◽  
Author(s):  
Zhang Min ◽  
Lu Hui-Xia ◽  
Xie Bo ◽  
Xin Qi
Keyword(s):  
Quality Control ◽  
Repeated Measurements ◽  
Quality Controls ◽  
Assay Procedure ◽  
Control Serum ◽  
Quality Control Materials ◽  
Control Survey ◽  
Accuracy Of Measurement ◽  
The Mean ◽  
Preparation And Evaluation

AbstractBackground:This research was aimed at preparing laboratory quality control materials for the detection of IgG anti-A/B and evaluating them in preliminary applications.Methods:Mixed IgG anti-A and anti-B sera were used as quality controls for measuring IgG anti-A/B titers. The quality control materials were packaged with sodium azide as preservative, and stored at –30°C. Twenty repeated measurements were done in succession. After the quality control values were determined, the quality control materials were used preliminarily. Quality controls and the untested blood samples were assayed at the same time within 6 months.Results:The mean IgG anti-A titer of the high-value quality control serum was 1:550 and ranged from 1:225 to 1:1100 for the control. The mean IgG anti-B titer of the high-value quality control serum was 1:269 and ranged from 1:135 to 1:538 for the control. The mean IgG anti-A and B titer of the low-value control serum was 1:32, with a quality control range of 1:16–1:64.Conclusions:Laboratory quality control materials in the measurement of IgG anti-A/B titers were developed successfully. Standardization of the assay procedure and quality control survey would be necessary for the accuracy of measurement.

Development of a stable lipoprotein diluent for use in reconstituting lyophilized human serum for the preparation of clear, hyperlipidemic quality-control materials.

1979 ◽  
Vol 25 (8) ◽  
pp. 1377-1380 ◽  
Author(s):  
G J Proksch ◽  
D P Bonderman
Keyword(s):  
Quality Control ◽  
Sodium Bicarbonate ◽  
Human Serum ◽  
Simple System ◽  
Lipoprotein Concentration ◽  
Control Serum ◽  
Quality Control Materials

Abstract We describe a simple system for the preparation of a hyperlipidemic control serum. Beta- and pre-beta-lipoproteins are removed from the serum and prepared as a stable diluent; the extracted serum is then lyophilized. Upon addition of the lipoprotein diluent, which was observed to contain only liproprotein and sodium bicarbonate, the serum reconstitutes rapidly, usually within 5 min. By a suitable adjustment of the lipoprotein concentration in the diluent, a hyperlipidemic control serum may be produced with desired concentrations of lipids. Because the lipoproteins are not included in the destructive lyophilization step, the resulting product has remarkable clarity, precision, and stability.

Long-term stability of a stabilized liquid quality-control serum.

1981 ◽  
Vol 27 (8) ◽  
pp. 1448-1452 ◽  
Author(s):  
A E Hartmann ◽  
R D Juel ◽  
R N Barnett
Keyword(s):  
Quality Control ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Linear Regression Coefficient ◽  
Term Stability ◽  
Long Term Stability ◽  
Control Serum ◽  
Quality Control Materials ◽  
Refrigerator Temperature

Abstract To evaluate the long-term stability of a new liquid quality-control serum ("Decision", Beckman Instruments, Inc.) stabilized with ethylene glycol (330 mL/L), we analyzed it for 22 commonly measured analytes during storage at 2--8 degrees C for 24 days or -15 to -20 degrees C for 55 weeks. Three separate laboratories replicated the analyses, using various analytical methodologies. The data were subjected to linear regression analysis, regressing concentration on time. Analytes were considered unstable when the linear regression coefficient was unequal to zero with 95% or greater probability in all three laboratories. By this criterion all of the analytes were stable for at least 24 days when the control serum was stored at refrigerator temperature and for at least 55 weeks at freezer temperature. We conclude this material is a satisfactory substitute for existing lyophilized quality-control materials and offers certain advantages: stability, vial-to-vial uniformity, decreased waste, and eliminated reconstitution.

Validation of the HEMOCLOT® Direct Thrombin Inhibitor Assay for Dabigatran by Comparison with a Validated LC-MS/MS Method in Plasma Samples From Patients After Major Orthopaedic Surgery

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2307-2307
Author(s):  
Joachim Stangier ◽  
Bengt I Eriksson ◽  
Michael H Huo ◽  
Richard J Friedman ◽  
Ola E Dahl ◽  
...  
Keyword(s):  
Quality Control ◽  
Dabigatran Etexilate ◽  
Thrombin Inhibitors ◽  
Study Endpoint ◽  
Direct Thrombin Inhibitors ◽  
Plasma Samples ◽  
Quality Controls ◽  
The Mean ◽  
Control Samples

Abstract Abstract 2307 Introduction: Although therapy with dabigatran etexilate does not require routine blood coagulation monitoring, under some clinical scenarios (e.g., severe or life-threatening bleeding, overdose or emergency surgery) a simple assay may be valuable. The HEMOCLOT® direct thrombin inhibitors assay (HYPHEN BioMed, France, CK002K), in conjunction with calibration standards and quality controls, allows the accurate and precise determination of dabigatran concentrations within a range of 50–500 ng/mL. Calibration and standardization of the assay minimizes intra- and interlaboratory variability. The present study was conducted to confirm the accuracy and reproducibility of the HEMOCLOT® assay in samples derived from patients undergoing total hip arthroplasty taking dabigatran etexilate for the prevention of venous thromboembolism in the RE-NOVATE® II trial. Methods: Dabigatran concentrations in low- and high dabigatran quality control samples were determined by a validated liquid chromatography/tandem mass spectrometry (LC-MS/MS) method (providing concentrations of 122 ng/mL and 285 ng/mL, respectively) and by back-calculation from thrombin times obtained in the calibrated HEMOCLOT® assay. Precision and accuracy of the HEMOCLOT® assay were determined by comparison of results. A total of 100 samples collected 2 hours post-dose in citrate were analyzed by both HEMOCLOT® and LC-MS/MS. The primary study endpoint was the comparison of total dabigatran concentrations determined by both methods. Results: Total assay imprecision for low dabigatran quality control samples was 2.6% coefficient of variation, with precision (repeatability) within-run 2.1%, between-run 1.4%, and between-day 0.6%. The respective values for high dabigatran samples were 2.8%, 1.8%, 2.0% and 0.9%. In the analysis of accuracy, the mean deviation of the calculated dabigatran concentration from the 122 ng/mL dabigatran sample target value was 14%, and from the 285 ng/mL dabigatran sample was –0.08%. In general, quality control sample concentrations of dabigatran were within ± 20% of the target concentration (acceptance limit). A total of 97 samples from patients provided valid data for the comparison of methods. The range of dabigatran concentrations was 68–438 ng/mL. The mean bias between the dabigatran concentrations determined by HEMOCLOT® (test) and LC-MS/MS (reference) was –8.9% (95% confidence interval –11.9 to –6.0%), with 95% limits of agreement of –37.7% to 19.8%. Conclusions: The HEMOCLOT® direct thrombin inhibitors assay in conjunction with dabigatran standards and quality controls is suitable for the precise quantitative determination of dabigatran in citrate plasma samples. The accuracy is considered acceptable for the intended use of the assay, i.e., identifying patients with very high dabigatran concentrations. Disclosures: Stangier: Boehringer Ingelheim: Employment. Eriksson:Bristol-Myers Squibb: Consultancy; Bayer: Consultancy; Astellas: Consultancy. Huo:Boehringer Ingelheim: Consultancy. Friedman:Johnson and Johnson: Consultancy. Feuring:Boehringer Ingelheim: Employment.

Quality of Commercially Available Controls in Laser Immunonephelometry

1980 ◽  
Vol 17 (4) ◽  
pp. 178-182 ◽  
Author(s):  
Gerald Shulman
Keyword(s):  
Quality Control ◽  
Reference Sample ◽  
Radial Immunodiffusion ◽  
Mean Values ◽  
Serum Pool ◽  
Control Serum ◽  
Specific Proteins ◽  
Quality Control Materials ◽  
Working Standards

Lack of accuracy in expressing concentrations of specific proteins in different lots of Hyland calibrating reference and quality control materials, supplied for the Hyland PDQ laser nephelometer, prompted an attempt to find alternative and more reliable calibrating materials available commercially. Laser grade (Atlantic Antibodies) and radial immunodiffusion grade materials (Behring Diagnostics) were evaluated in this study. Using Atlantic Antibodies' calibrator, only five of 11 specific proteins assayed in Atlantic control serum were within acceptable ranges; precision was less than that using Hyland materials of identical lots. Mean values for each of 10 of the same 11 specific proteins of Behring control plasma, assayed against Behring stabilised human serum, were within manufacturers' acceptable ranges; however, precision was less than that with Hyland materials from identical lots. Nine of the 11 specific proteins in a frozen serum pool sample, measured on the laser nephelometer, agreed well with results of the specific proteins measured by radial immunodiffusion, using the same Behring calibration and quality control. Only the Hyland materials were prediluted for use, which explains the greater precision that was obtained. Intercomparison of concentrations, as expressed by respective manufacturers, was largely unacceptable. Based on these results there is need, until satisfactory reagents become available, to standardise on one parent Hyland reference sample giving best precision and to calibrate all subsequent working standards against the parent reference.

SERUM TRIIODOTHYRONINE DETERMINATION BY SATURATION ANALYSIS

1973 ◽  
Vol 72 (4) ◽  
pp. 714-726 ◽  
Author(s):  
A. Burger ◽  
B. Miller ◽  
C. Sakoloff ◽  
M. B. Vallotton
Keyword(s):  
Ionic Strength ◽  
Limit Of Detection ◽  
Improved Method ◽  
Accuracy Of Measurement ◽  
Tracer Amount ◽  
The Mean ◽  
Physiological Values ◽  
Hyperthyroid Patients ◽  
Solvent Blank

ABSTRACT An improved method for the determination of serum triiodothyronine (T3) has been developed. After addition of a tracer amount of the hormone, T3 was extracted from 1 ml serum under conditions of pH and ionic strength which favoured T3 extraction (89%) over thyroxine (T4) extraction (58%). Chromatography of the extracted material on Sephadex LH-20 separated T3 completely from residual T4. The T3 eluate was dried, then re-dissolved in 0.5 ml NaOH 0.04 n. To 0.2 ml duplicate aliquots, a standard amount of TBG was added for the competitive protein analysis. After one hour incubation at 4°C, separation of bound from free T3 was achieved on small Sephadex G-25 columns. Overall recovery was 67 ± 10.8% and correction for the loss was made. The solvent blank was 37 ± 27 (sd) ng/100 ml. Accuracy of measurement of known quantities of T3 added to serum was 98.4%. The coefficient of variation within the assay was 6.2% and between the assays it was 11.4%. The limit of detection (0.1 ng) corresponded to a concentration of 25 ng/100 ml. T4 added to serum did not interfere with T3 determination until high non-physiological values were reached. The mean ± sd serum T3 in 54 euthyroid subjects was 153 ± 58 ng/100 ml and in 24 hyperthyroid patients it was 428 ±186 ng/100 ml; 4 out of the 24 hyperthyroid values were within 2 sd of the mean euthyroid group. All the values found in the euthyroid group were well above the limit of detection of the method.

Kidney function decline is associated with an accelerated increase in plasma homocysteine in older adults: a longitudinal study

2021 ◽  
pp. 1-21
Author(s):  
Hui Zhang ◽  
Yi Li ◽  
Meng Hao ◽  
Xiaoyan Jiang ◽  
Jiucun Wang ◽  
...  
Keyword(s):  
Kidney Function ◽  
Repeated Measurements ◽  
Baseline Survey ◽  
Mixed Effect ◽  
Pronounced Increase ◽  
Crude Model ◽  
The Mean ◽  
Kidney Function Decline ◽  
Over Time

Abstract Background: Few studies have been conducted to investigate the association of kidney function decline with the trajectories of homocysteine (Hcy) over time, using repeated measurements. We aimed to investigate the association of kidney function with changes in plasma Hcy levels over time. Methods: Data were collected from the Rugao Longevity and Ageing Study. In detail, plasma Hcy and creatinine levels were measured in both waves (waves 2, 3 and 4) during the 3.5-year follow-up (N = 1135). Wave 2 was regarded as the baseline survey. The estimated glomerular filtration rate (eGFR) was calculated based on creatinine. Subjects were categorized into four groups according to quartiles of eGFR at baseline. Linear mixed-effect models were used to investigate the association of eGFR with subsequent plasma Hcy levels. Results: The mean eGFR at baseline was 90.84 (11.42) mL/min/1.73 m2. The mean plasma Hcy level was 14.09 (6.82) at baseline and increased to 16.28 (8.27) and 17.36 (10.39) μmol/L during follow-ups. In the crude model, the interaction between time and eGFR at baseline was significant (β = −0.02, 95% CI: −0.02 to −0.01, p = 0.002). After adjusting for confounding factors, a significant relationship remained (β = −0.02, 95% CI: −0.02 to −0.01, p = 0.003), suggesting that kidney function decline at baseline was associated with a faster increase in Hcy levels. Conclusion: Kidney function decline is associated with a more pronounced increase in plasma Hcy levels. Further studies with longer follow-up periods and larger sample sizes are needed to validate our findings.

A modified sonographic technique for assessment of gastric emptying of liquid

2003 ◽  
Vol 44 (3) ◽  
pp. 340-342 ◽  
Author(s):  
J. F. Pedersen
Keyword(s):  
Gastric Emptying ◽  
Repeated Measurements ◽  
Intraindividual Variation ◽  
Ultrasound Technique ◽  
Liquid Meal ◽  
Ultrasound Monitoring ◽  
Gastric Emptying Time ◽  
The Mean ◽  
Antral Area ◽  
Emptying Time

Purpose: Ultrasound scanning is replacing scintigraphy in studies of gastric emptying of liquid, but both have considerable day-to-day variability. This study describes a modified ultrasound technique for assessing gastric emptying of liquid, and evaluates the inter- and intraindividual variation in emptying time. Material and Methods: On different days, each of 12 healthy volunteers had meals of 350 ml broth. The antral area was measured at sonography 5 times before the meal as a baseline, and every 1–4 min after the meal. The time until the antral area had decreased to 150% of baseline (T150) was determined and used as surrogate expression of gastric emptying time. Results: The mean T150 for a broth meal was 12.6 min (range 5–21) and 13.5 min (6–23) (first and second meal, respectively). The standard deviation of the differences between the 12 pairs of repeated measurements was 3.1 min and the coefficient of variation was 24%. Conclusion: Ultrasound monitoring of antral size after a liquid meal is a well suited method for assessing gastric emptying of liquid.

scholarly journals Daily Quality Control in CD3+and CD4+T Cell Estimation by the FACSCount System at a Tertiary Care Center in South India

2012 ◽  
Vol 19 (10) ◽  
pp. 1693-1696 ◽  
Author(s):  
Veena V. Ramalingam ◽  
Monika Mani ◽  
Vijayanand C. Sundaresan ◽  
Ramesh J. Karunaiya ◽  
Jaiprasath Sachithanandham ◽  
...  
Keyword(s):  
Quality Control ◽  
T Cell ◽  
South India ◽  
Care Center ◽  
Tertiary Care ◽  
Cd4 T Cell ◽  
Internal Quality ◽  
Cell Counts ◽  
Resource Poor ◽  
The Mean

ABSTRACTCD4+T cell count estimations are subject to high variations; hence, in this study, the previous day's tested samples were included routinely as the internal quality controls. The percentages of variation of the 2-day values were analyzed for 280 observations and the mean variation for CD4+and CD3+T cell counts ranged from 5.21% to 9.66%. This method is a good internal quality control (IQC) procedure for the estimation of CD3+and CD4+T cell counts in resource-poor settings.

scholarly journals Overview of large building testing in Baltic countries

2020 ◽  
Vol 172 ◽  
pp. 05007
Author(s):  
Andrejs Nitijevskis ◽  
Vladislavs Keviss
Keyword(s):  
Quality Control ◽  
Pressure Difference ◽  
Leakage Rate ◽  
Air Leakage ◽  
Baltic Countries ◽  
Measurement Results ◽  
The Mean ◽  
Mandatory Testing ◽  
Air Leakage Rate ◽  
Large Building

The objectives of this paper are to review measurements of airtightness of 2 large building groups – middle size shops, and warehouses/distribution centres. The mean air leakage rate at 50 Pa pressure difference q50 was 1.04 m3/m2h and 1.35 m3/m2h for shops and warehouses respectively. Analysis of measurement results is valuable because it allows to make a conclusion about compliance of national and corporative construction airtightness norms with actual air barrier condition on a comissioning stage. In the concluding part of the study there are suggested ways to improve air barrier such as review of construction norms, implementation of a mandatory testing and quality control of a measurement.

In Reply: Limitations to Quality Control Materials for CO-oximeters

CHEST Journal ◽  
1985 ◽  
Vol 87 (3) ◽  
pp. 409-410
Author(s):  
John R. Spurzem ◽  
John W. Shigeoka ◽  
H. William Bonekat
Keyword(s):  
Quality Control ◽  
Quality Control Materials
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