Analytical evaluation of the Dade Behring Dimension RxL automated N-Terminal proBNP (NT-proBNP) method and comparison with the Roche Elecsys 2010

2005 ◽  
Vol 43 (11) ◽  
Author(s):  
Francesca Di Serio ◽  
Vincenzo Ruggieri ◽  
Lucia Varraso ◽  
Rosalisa De Sario ◽  
Angela Mastrorilli ◽  
...  
Keyword(s):  
Detection Limit ◽  
Healthy Subjects ◽  
Effect Of Temperature ◽  
Serum Samples ◽  
Coefficients Of Variation ◽  
Sample Stability ◽  
The Matrix ◽  
Heparin Plasma ◽  
Roche Diagnostics ◽  
Age And Sex

AbstractMethods to quantify B-type natriuretic peptide (BNP) and N-terminal-propeptide (NT-proBNP) in plasma or serum samples are well established. We assessed the analytical performance of the Dimension RxL NT-proBNP method (Dade-Behring). Evaluation of different sample types was carried out. Controls and heparin plasma pools were used to determine the detection limit, precision, and linearity. Sample stability and the effect of interfering substances on the NT-proBNP concentrations were evaluated. Agreement between Dimension RxL and Elecsys 2010 (Roche Diagnostics) NT-proBNP methods was assessed. The influence of age and sex on NT-proBNP concentrations was evaluated in healthy subjects. Heparin plasma should be the matrix of choice. The detection limit was 2.0ng/L. The total imprecision was 2.6–3.6% for concentrations from 231 to 9471ng/L; mean NT-proBNP concentrations of 21 and 15ng/L were associated with coefficients of variation of 9.9% and 14.7%, respectively. The method was linear up to 32,650ng/L. There was no effect of temperature, freeze-thaw cycles and interfering substances. A bias was detected when Dimension RxL and Elecsys 2010 NT-proBNP methods were compared. Age and sex were significantly and independently related to NT-proBNP concentrations. The Dimension RxL NT-proBNP method, like the Elecsys 2010, is suitable for routine use in the diagnosis of heart failure.

scholarly journals Highly specific radioimmunoassay for human insulin based on immune exclusion of all insulin precursors

1998 ◽  
Vol 44 (7) ◽  
pp. 1504-1513 ◽  
Author(s):  
Michelle Deberg ◽  
Paule Houssa ◽  
Bruce H Frank ◽  
Françoise Sodoyez-Goffaux ◽  
Jean-Claude Sodoyez
Keyword(s):  
Monoclonal Antibodies ◽  
Detection Limit ◽  
Affinity Constant ◽  
Serum Samples ◽  
C Peptide ◽  
Specific Radioimmunoassay ◽  
Coefficients Of Variation ◽  
Patients With Diabetes ◽  
A Chain ◽  
Immune Exclusion

Abstract We describe a rapid and simple insulin RIA in which proinsulin and conversion intermediates do not interfere. Three monoclonal antibodies (S1, S2, and S53) were selected for their specificity (directed, respectively, against the B10 region, the junction between A chain and C-peptide, and the junction between B chain and C-peptide), their affinity constant (∼1010 L/mol), and their interactive properties in mixture. S2 and S53 were able to bind simultaneously to the same proinsulin molecule, whereas neither could bind simultaneously with S1. Preincubation of serum samples with an excess of S2 resulted in capture of proinsulin and conversion intermediates modified at the junction between B chain and C-peptide into immune complexes that no longer reacted with S1. Similarly, preincubation with S53 prevented proinsulin and conversion intermediates modified at the junction between A chain and C-peptide from reacting with S1. Preincubation with an excess of both S2 and S53 left insulin as the sole reactant with S1. Thus, separation of insulin precursors from insulin by mutually exclusive antibodies is feasible, and on the basis of this new principle, a highly specific RIA for insulin was designed. The detection limit was 11 pmol/L, and the inter- and intraassay coefficients of variation were 11% and 5%, respectively. The potential of the assay for use in clinical studies was verified by application to serum samples from control subjects and patients with diabetes or insulinoma.

Total lab automation: sample stability of clinical chemistry parameters in an automated storage and retrieval module

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kobe Vercruysse ◽  
Stijn Lambrecht ◽  
Matthijs Oyaert
Keyword(s):  
Clinical Chemistry ◽  
Fixed Time ◽  
Economic Benefits ◽  
Plasma Samples ◽  
Serum Samples ◽  
Storage And Retrieval ◽  
Sample Stability ◽  
Heparin Plasma ◽  
Variation Database ◽  
Automated Storage

Abstract Objectives Automated storage and retrieval modules (SRM), as part of total lab automation (TLA) systems, offer tremendous practical and economic benefits. In contrast to manual storage systems, SRMs indicate continuous motion of samples and may leave samples prone to temperature fluctuations. This study investigates analyte stability in serum and heparin plasma within an automated storage module. Methods The stability of 28 common biochemistry analytes was investigated using 57 freshly obtained routine serum samples and 42 lithium-heparin plasma samples. Following baseline measurement, samples were stored at 2–8 °C in the automated SRM of the Accelerator a3600 TLA and reanalyzed at fixed time points (2, 4, 8, 12, 24, 48 and 72 h) on the Abbott Architect c16000 chemistry analyzer. The concentration at each time point was expressed as %-difference to the baseline value and mean results were compared to the criteria for desirable bias derived from the biological variation database. Results Nine of the analytes exceeded the bias criterion within 72 h after initial measurement in either serum samples, plasma samples or both. Lithium-heparin plasma samples showed increasing values for phosphor, potassium and lactate dehydrogenase (LDH), which were only considered stable for respectively 24, 12 and 4 h, glucose was considered stable for 8 h. Electrolyte concentrations and LDH activity significantly increased in serum samples beyond 48 h. Bicarbonate should not be performed as add-on test at all. Conclusions The presented data indicate that the conditions within an SRM have no clinical impact on sample stability and allow stable measurement of routine analytes within 72 h, comparable to manual storage facilities.

scholarly journals Determination of Retinol-Binding Protein in Serum by Kinetic Immunonephelometry with Polyethylene Glycol Pretreatment

1984 ◽  
Vol 21 (6) ◽  
pp. 484-487 ◽  
Author(s):  
M J Hallworth ◽  
Jacqueline Calvin ◽  
C P Price
Keyword(s):  
Polyethylene Glycol ◽  
Detection Limit ◽  
Binding Protein ◽  
Regression Line ◽  
Retinol Binding Protein ◽  
Serum Samples ◽  
Coefficients Of Variation ◽  
Method Yield ◽  
Scattering Material

This work describes the use of polyethylene glycol as a pretreatment reagent to remove endogenous light scattering material from serum samples prior to automated immunonephelometric analysis on a centrifugal analyser. An assay system for retinol-binding protein is described, which allows rapid (10 minutes) quantitation of retinol-binding protein in serum samples with a detection limit of 5 mg/L and between-assay coefficients of variation ranging from 2·9% to 4·0%. The assay range is 5–80 mg/L and accuracy comparisons with a Mancini single radial immunodiffusion method yield a regression line y=0·89x+0·52 ( r=0·98, n=22). The problem of analyte precipitation associated with use of pretreatment regimes is discussed.

Solid-phase enzymoimmunoassay of estrone in serum.

1988 ◽  
Vol 34 (9) ◽  
pp. 1843-1846 ◽  
Author(s):  
J Folan ◽  
J P Gosling ◽  
P F Fottrell
Keyword(s):  
Detection Limit ◽  
Correlation Coefficient ◽  
Diethyl Ether ◽  
Analytical Procedure ◽  
Solid Phase ◽  
Serum Samples ◽  
Microtiter Plates ◽  
Coefficients Of Variation ◽  
High Concentrations ◽  
Working Day

Abstract This rapid solid-phase enzymoimmunoassay for estrone in serum or plasma is done on microtiter plates after the serum is extracted with diethyl ether. No chromatographic or centrifugation steps are involved. The detection limit of the assay is 380 fg per well (28 pmol/L). Intra- and interassay coefficients of variation for the assay of low, medium, and high concentrations of estrone in plasma were respectively 4.4, 9.3; 2.3, 9.1; and 2.0, 6.3 percent. There was a good correlation (correlation coefficient 0.95) between estrone concentrations measured with this assay and with a commercial radioimmunoassay. The analytical procedure is simple, and one person can assay 80 serum samples per working day. We conclude that the assay is very suitable for serum estrone measurements and is more convenient than published radioimmunoassays.

scholarly journals Multicenter performance evaluation of a second generation cortisol assay

2017 ◽  
Vol 55 (6) ◽  
pp. 826-835 ◽  
Author(s):  
Michael Vogeser ◽  
Jürgen Kratzsch ◽  
Yoon Ju Bae ◽  
Mathias Bruegel ◽  
Uta Ceglarek ◽  
...  
Keyword(s):  
Second Generation ◽  
Reference Ranges ◽  
Good Precision ◽  
Healthy Individuals ◽  
Serum Samples ◽  
Intermediate Precision ◽  
Coefficients Of Variation ◽  
Liquid Chromatography Tandem Mass ◽  
Cortisol Levels ◽  
Roche Diagnostics

Abstract Background: Untreated disorders of the adrenocortical system, such as Cushing’s or Addison’s disease, can be fatal, and accurate quantification of a patient’s cortisol levels is vital for diagnosis. The objective of this study was to assess the analytical performance of a new fully-automated Elecsys® Cortisol II assay (second generation) to measure cortisol levels in serum and saliva. Methods: Four European investigational sites assessed the intermediate precision and reproducibility of the Cortisol II assay (Roche Diagnostics) under routine conditions. Method comparisons of the Cortisol II assay vs. liquid chromatography-tandem mass spectrometry (LC-MS/MS), the gold standard for cortisol measurement, were performed. Cortisol reference ranges from three US sites were determined using samples from self-reported healthy individuals. Results: The coefficients of variation (CVs) for repeatability, intermediate precision, and reproducibility for serum samples were ≤2.6%, ≤5.8%, and ≤9.5%, respectively, and for saliva were ≤4.4% and ≤10.9%, and ≤11.4%, respectively. Agreement between the Cortisol II assay and LC-MS/MS in serum samples was close, with a slope of 1.02 and an intercept of 4.473 nmol/L. Reference range samples were collected from healthy individuals (n=300) and serum morning cortisol concentrations (5–95th percentile) were 166.1–507 nmol/L and afternoon concentrations were 73.8–291 nmol/L. Morning, afternoon, and midnight saliva concentrations (95th percentile) were 20.3, 6.94, and 7.56 nmol/L, respectively. Conclusions: The Cortisol II assay had good precision over the entire measuring range and had excellent agreement with LC-MS/MS. This test was found suitable for routine diagnostic application and will be valuable for the diagnosis of adrenocortical diseases.

scholarly journals Intra- and inter-cycle variability of anti-Müllerian hormone (AMH) levels in healthy women during non-consecutive menstrual cycles: the BICYCLE study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Marieke Biniasch ◽  
Ruediger Paul Laubender ◽  
Martin Hund ◽  
Katharina Buck ◽  
Christian De Geyter
Keyword(s):  
Biological Variability ◽  
Single Cycle ◽  
Serum Samples ◽  
Menstrual Cycles ◽  
Healthy Women ◽  
Analytical Variability ◽  
Coefficients Of Variation ◽  
Periodic Regression ◽  
Roche Diagnostics ◽  
Gonadotropin Dosage

Abstract Objectives Determine variability of serum anti-Müllerian hormone (AMH) levels during ovulatory menstrual cycles between different women (inter-participant), between non-consecutive cycles (inter-cycle) and within a single cycle (intra-cycle) in healthy women. Methods Eligible participants were women aged 18–40 years with regular ovulatory menstrual cycles. Serum samples were collected every second day during two non-consecutive menstrual cycles. AMH levels were measured in triplicate using the Elecsys® AMH Plus immunoassay (Roche Diagnostics). AMH level variability was evaluated using mixed-effects periodic regression models based on Fourier series. The mesor was calculated to evaluate inter-participant and inter-cycle variability. Inter- and intra-cycle variability was evaluated using peak-to-peak amplitudes. Separation of biological and analytical coefficients of variation (CVs) was determined by analysing two remeasured AMH levels (with and without original AMH levels). Results A total of 47 women were included in the analysis (42 assessed over two cycles; five one cycle only). CV of unexplained biological variability was 9.61%; analytical variability was 3.46%. Inter-participant variability, given by time-series plots of AMH levels, was greater than inter-cycle variability. Between individual participants, both mesor and peak-to-peak amplitudes proved variable. In addition, for each participant, intra-cycle variability was higher than inter-cycle variability. Conclusions Inter-participant and intra-cycle variability of AMH levels were greater than inter-cycle variability. Unexplained biological variability was higher than analytical variability using the Elecsys AMH Plus immunoassay. Understanding variability in AMH levels may aid in understanding differences in availability of antral ovarian follicles during the menstrual cycle, which may be beneficial in designing gonadotropin dosage for assisted reproductive technology.

Sensitive, practical bioassay of thyrotropin, with use of FRTL-5 thyroid cells and magnetizable solid-phase-bound antibodies.

1988 ◽  
Vol 34 (11) ◽  
pp. 2360-2364 ◽  
Author(s):  
Y Tokuda ◽  
K Kasagi ◽  
Y Iida ◽  
H Hatabu ◽  
A Hidaka ◽  
...  
Keyword(s):  
Detection Limit ◽  
Human Serum ◽  
Solid Phase ◽  
New Method ◽  
Camp Production ◽  
Serum Samples ◽  
Thyroid Cells ◽  
Immunoaffinity Purification ◽  
Coefficients Of Variation ◽  
Hypothyroid Patients

Abstract We have developed a new method for assessing the bioactivity of thyrotropin (TSH) in human serum by measuring cAMP production in FRTL-5 thyroid cells as an index of stimulation. To eliminate serum inhibitors of the cAMP response to TSH, we purified samples by mixing them with anti-TSH antibodies coupled to magnetizable particles. This method of immunoaffinity purification was simple and suitable for the measurement of a large number of samples. The detection limit of the bioassay was 3.13 milli-int. units of human TSH per liter. Intra-assay and interassay coefficients of variation ranged from 5.4 to 8.6% and from 12.6 to 21.5%, respectively. The concentrations of bioassayable TSH closely correlated with those of immunoassayable TSH, both in the immunoaffinity-purified samples (r = 0.946, P less than 0.001) and in the serum samples (r = 0.945, P less than 0.001) from 14 euthyroid subjects and 53 hypothyroid patients with Hashimoto's thyroiditis. The bioactivity-to-immunoactivity ratio was almost constant (0.84 +/- 0.30; mean +/- SD) over the range of concentrations of immunoassayable TSH in serum, 6.3 to 177 milli-int. units/L. We also demonstrate that the technique is applicable to measurements of bioactivities of circulating forms of immunoreactive TSH in different pathophysiological conditions.

scholarly journals Evaluating the performance of an updated high-sensitivity troponin T assay with increased tolerance to biotin

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander von Meyer ◽  
Gesa Albert ◽  
Stefan Kunzelmann ◽  
Christopher Rank ◽  
Rainer Zerback ◽  
...  
Keyword(s):  
Serum Sample ◽  
Troponin T ◽  
High Sensitivity ◽  
Sensitive Assay ◽  
Decision Limit ◽  
Coefficients Of Variation ◽  
Assay Performance ◽  
Heparin Plasma ◽  
High Sensitivity Troponin T ◽  
Roche Diagnostics

AbstractObjectivesBiotin >20 ng/mL may interfere with the Elecsys® Troponin T-high sensitive assay (cTnT-hs; Roche Diagnostics International Ltd). We evaluated the performance of an updated assay, cTnT-hs*, which was designed to reduce biotin interference.MethodscTnT-hs* assay performance was assessed using up to two applications (18 min/9 min) on three analyzers (cobas e 411/cobas e 601/cobas e 801). Biotin interference was determined by measuring recovery in an 11-sample series dilution with biotin ranging from 0–3600 ng/mL. Repeatability/reproducibility were evaluated in five serum sample pools (n=75 each). Method comparisons tested: cTnT-hs* vs. cTnT-hs (18 min/cobas e 601); cTnT-hs* assay 18 vs. 9 min (cobas e 601); cTnT-hs* (18 min) on cobas e 601 vs. cobas e 411 and cobas e 601 vs. cobas e 801. Concordance at the 99th percentile decision limit between cTnT-hs* and cTnT-hs (9 min/cobas e 601) was calculated using 300 lithium-heparin plasma samples and a 14 ng/L assay cutoff.ResultscTnT-hs* assay (18 min/cobas e 601) recovery was ≥96% for biotin ≤1250 ng/mL. Across all applications/analyzers, coefficients of variation for repeatability/reproducibility with the cTnT-hs* assay were <5% in most serum sample pools (mean cardiac troponin T: 8.528–9484 ng/L). High correlation (Pearson’s r=1.000) was demonstrated for all method comparisons. Concordance at the 99th percentile decision limit was high between the cTnT-hs* and cTnT-hs assays.ConclusionsThe updated cTnT-hs* assay may provide greater tolerance to biotin interference, and shows good analytical and clinical agreement/concordance with the previous cTnT-hs assay.

scholarly journals COVID-19 Vaccine mRNABNT162b2 Elicits Human Antibody Response in Milk of Breastfeeding Women

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 785
Author(s):  
Maurizio Guida ◽  
Daniela Terracciano ◽  
Michele Cennamo ◽  
Federica Aiello ◽  
Evelina La Civita ◽  
...  
Keyword(s):  
Breast Milk ◽  
Antibody Response ◽  
Human Milk ◽  
Human Antibody ◽  
Serum Antibodies ◽  
Serum Samples ◽  
Low Concentration ◽  
Milk Samples ◽  
Milk Antibodies ◽  
Roche Diagnostics

Objective: The objective of this research is to demonstrate the release of SARS-CoV-2 Spike (S) antibodies in human milk samples obtained by patients who have been vaccinated with mRNABNT162b2 vaccine. Methods: Milk and serum samples were collected in 10 volunteers 20 days after the first dose and 7 seven days after the second dose of the mRNABNT162b2 vaccine. Anti-SARS-CoV-2 S antibodies were measured by the Elecsys® Anti-SARS-CoV-2 S ECLIA assay (Roche Diagnostics AG, Rotkreuz, Switzerland), a quantitative electrochemiluminescence immunometric method. Results: At first sample, anti-SARS-CoV-2 S antibodies were detected in all serum samples (103.9 ± 54.9 U/mL) and only in two (40%) milk samples with a low concentration (1.2 ± 0.3 U/mL). At the second sample, collected 7 days after the second dose, anti-SARS-CoV-2 S antibodies were detected in all serum samples (3875.7 ± 3504.6 UI/mL) and in all milk samples (41.5 ± 47.5 UI/mL). No correlation was found between the level of serum and milk antibodies; the milk antibodies/serum antibodies ratio was on average 2% (range: 0.2–8.4%). Conclusion: We demonstrated a release of anti-SARS-CoV-2 S antibodies in the breast milk of women vaccinated with mRNABNT162b2. Vaccinating breastfeeding women could be a strategy to protect their infants from COVID-19 infection.

scholarly journals Folate and Cobalamin Serum Levels in Healthy Children and Adolescents and Their Association with Age, Sex, BMI and Socioeconomic Status

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 546
Author(s):  
Paulina Kreusler ◽  
Mandy Vogel ◽  
Anja Willenberg ◽  
Ronny Baber ◽  
Yvonne Dietz ◽  
...  
Keyword(s):  
Socioeconomic Status ◽  
Children And Adolescents ◽  
Serum Levels ◽  
Population Based ◽  
Research Centre ◽  
Healthy Children ◽  
Serum Samples ◽  
Lms Method ◽  
Healthy Participants ◽  
Age And Sex

This study proposes age- and sex-specific percentiles for serum cobalamin and folate, and analyzes the effects of sex, age, body mass index (BMI), and socioeconomic status (SES) on cobalamin and folate concentrations in healthy children and adolescents. In total, 4478 serum samples provided by healthy participants (2 months–18.0 years) in the LIFE (Leipzig Research Centre for Civilization Diseases) Child population-based cohort study between 2011 and 2015 were analyzed by electrochemiluminescence immunoassay (ECLIA). Continuous age-and sex-related percentiles (2.5th, 10th, 50th, 90th, 97.5th) were estimated, applying Cole’s LMS method. In both sexes, folate concentrations decreased continuously with age, whereas cobalamin concentration peaked between three and seven years of age and declined thereafter. Female sex was associated with higher concentrations of both vitamins in 13- to 18-year-olds and with higher folate levels in one- to five-year-olds. BMI was inversely correlated with concentrations of both vitamins, whilst SES positively affected folate but not cobalamin concentrations. To conclude, in the assessment of cobalamin and folate status, the age- and sex-dependent dynamic of the respective serum concentrations must be considered. While BMI is a determinant of both vitamin concentrations, SES is only associated with folate concentrations.

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