Analytical Performance of the NOVEOS Allergen-Specific IgE Assay: Precision and Detection Limit Studies.

2018 ◽  
Author(s):  
Douglas  Evans
Keyword(s):  
Detection Limit ◽  
Specific Ige ◽  
Analytical Performance ◽  
Assay Precision

scholarly journals Adrenomedullin(1–52) measured in human plasma by radioimmunoassay: plasma concentration, adsorption, and storage

1998 ◽  
Vol 44 (3) ◽  
pp. 571-577 ◽  
Author(s):  
Lynley K Lewis ◽  
Mary W Smith ◽  
Timothy G Yandle ◽  
A Mark Richards ◽  
M Gary Nicholls
Keyword(s):  
Plasma Concentration ◽  
Detection Limit ◽  
Normal Subjects ◽  
Hplc Separation ◽  
Freeze Thaw ◽  
Factors Influencing ◽  
Calcitonin Gene ◽  
Vasoactive Hormones ◽  
Assay Precision ◽  
And Storage

Abstract We describe a specific and sensitive RIA for human adrenomedullin (AM)(1–52). The detection limit and the concentration required for 50% inhibition of binding were 0.1 and 1.2 fmol/tube, respectively. Cross-reactivities with AM(1–12), AM(13–52), calcitonin gene-related peptide, amylin, and other vasoactive hormones were negligible. AM immunoreactivity in normal subjects ranged from 2.7 to 10.1 pmol/L (n = 44). We investigated factors influencing the recovery and measurement of AM in the assay. Recovery of labeled AM (>80%) was markedly higher than that of unlabeled AM (56%). Immunoreactivity of exogenous AM added to plasma decreased up to 70% over four freeze–thaw cycles, whereas endogenous AM was stable. Alkali-treated casein (1 g/L) reduced adsorption of AM to surfaces and significantly increased assay precision compared with bovine serum albumin (P <0.0001). HPLC separation of extracted plasma verified the presence of AM(1–52). We suggest that considerable care is needed to ensure that accurate and reproducible results are obtained from studies quantifying this peptide.

Chemiluminescence immunoassay of thyrotropin with acridinium-ester-labeled antibody evaluated and compared with two other immunoassays.

1987 ◽  
Vol 33 (11) ◽  
pp. 2096-2100 ◽  
Author(s):  
M P Bounaud ◽  
J Y Bounaud ◽  
M H Bouin-Pineau ◽  
L Orget ◽  
F Begon
Keyword(s):  
Detection Limit ◽  
Thyroid Function ◽  
Analytical Performance ◽  
Immunoradiometric Assay ◽  
Chemiluminescence Immunoassay ◽  
Hypothyroid Patients ◽  
Hyperthyroid Patients ◽  
Acridinium Ester

Abstract A new chemiluminometric immunoassay of thyrotropin (TSH) involves antibody labeled with acridinium ester ("Magic Lite System," Ciba Corning Diagnostic Corp.). The assay is rapid, with two incubations totaling 2.5 h, requires two standards per run, and takes 10 s per sample for the quantification step. Analytical performance, within- and between-run reproducibilities, and linearity were excellent. The detection limit is 0.04 milli-int. unit/L. Results correlated well with those obtained by immunoradiometric assay (RIA-gnost hTSH, Hoechst-Behring) and immunofluorometric assay (hTSH Delfia, LKB): r = 0.975. TSH measurements in 32 euthyroid subjects ranged from 0.4 to 4.8 milli-int. units/L (mean 1.35 milli-int. units/L). TSH values for 51 hypothyroid and subclinically hypothyroid patients ranged from 2 to 65 milli-int. units/L. TSH values for 33 hyperthyroid patients (less than 0.14 milli-int. unit/L, less than 0.04 milli-int. unit/L in 16 of the 33) were clearly lower than for most untreated euthyroid subjects. For 169 other individuals whose thyroid function was being routinely assessed. TSH ranged from 0.4 to 4.8 milli-int. units/L, three had TSH less than 0.14 milli-int. unit/L, and four had TSH between 0.14 and 0.4 milli-int. unit/L. This system is as efficient and reliable for screening for thyroid function as the two comparison systems.

Application of the CLSI EP15-A3 Guideline as an Alternative Troubleshooting Tool for Verification of Assay Precision

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S88-S88
Author(s):  
Jose Jara Aguirre ◽  
Karl Ness ◽  
Alicia Algeciras-Schimnich
Keyword(s):  
Quality Control ◽  
Carcinoembryonic Antigen ◽  
Laboratory Investigation ◽  
Analysis Of Variance ◽  
Experimental Approach ◽  
Biological Variation ◽  
Analytical Performance ◽  
Microsoft Excel ◽  
Before And After ◽  
Assay Precision

Abstract Introduction The CLSI EP15-A3 guideline “User Verification of Precision and Estimation of Bias” provides a simple experimental approach to estimate a method’s imprecision and bias. The objective is to determine if the laboratory precision performance of repeatability (SR) and within-laboratory imprecision (SWL) are in accordance to the manufacturer specification claims (MSCs). Objectives Evaluate the utility of the EP15-A3 protocol to verify method precision during a troubleshooting investigation and after major instrument maintenance, using a carcinoembryonic antigen (CEA) immunoassay as an example. Methods CEA was performed on the Beckman Coulter DxI (Beckman Coulter, Brea, CA). Quality control (QC) levels (L1: 2.89; L2: 21.10; L3: 39.10 ng/mL) (Bio-Rad Laboratories, Irvine, CA) were used. Each QC level was measured before and after instrument maintenance as follows: five replicates per run, one run per day, and during 5 days. Imprecision estimates (IEs) for SR (%CVR) and SWL (%CVWL) were calculated by one-way analysis of variance using Microsoft Excel Analyse-it software. Estimated imprecision was compared to MSC and desirable imprecision specifications based on biological variation (BV). Results A change in the analytical performance of CEA was detected by a decreased sigma-metric indicator. After a bias problem was ruled out, the observed %CVR for L1, L2, and L3 were 7.2%, 3.7%, and 4.8%, respectively. The %CVWL were 8.3%, 5.0%, and 5.5%, which exceeded the MSC of %CVWL~4.0% to 4.5%. After a laboratory investigation, major instrument maintenance was performed by the manufacturer. The %CVR and %CVWL estimates for L1, L2, and L3 after maintenance were 3.2%, 3.8%, 3.5% and 3.9%, 4.2%, 4.0%, respectively. After maintenance, the CEA performance was consistent with the MSC for each of the levels analyzed and within the BV impression goal of %CV ≤6.4. Conclusion CLSI EP15-A3 guideline is an alternative troubleshooting tool that can be used to investigate and verify method precision performance before and after significant instrument maintenance.

Intensity and Distribution of Background X-rays in Wavelength Dispersive Spectrometry

1987 ◽  
Vol 31 ◽  
pp. 507-514
Author(s):  
Tomoya Arai ◽  
Kazuhiko Omote
Keyword(s):  
Trace Elements ◽  
Detection Limit ◽  
Trace Element ◽  
Atomic Number ◽  
Analytical Performance ◽  
Background Intensity ◽  
X Rays ◽  
Wavelength Dispersive Spectrometry ◽  
Made In

In the speetrographie analysis of composite elements by fluorescent x-rays, significant developments have been made in low atomic number element measurement and improvement of analytical performance in trace element measurements.For the analysis of trace elements, background intensity governs analytical accuracies and the lowest detection limit in a sample.

scholarly journals The influence of NaCl and Na2SO4 as supporting electrolyte on analysis of lead (II) in seawater by stripping voltammetry using hanging mercury drop electrode

2014 ◽  
Vol 10 (3) ◽  
Author(s):  
Miratul Khasanah ◽  
Handoko Darmokusumo ◽  
. Rochmawati
Keyword(s):  
Detection Limit ◽  
Deposition Time ◽  
Supporting Electrolyte ◽  
Stripping Voltammetry ◽  
Deposition Potential ◽  
Analytical Performance ◽  
Hanging Mercury Drop Electrode ◽  
Current Signal ◽  
Mercury Drop Electrode ◽  
Stirring Rate

The influence of NaCl and Na2SO4 as supporting electrolyte on lead (II) analysis in seawater by stripping voltammetry was studied. The instrumental parameters obtained in this recent study were deposition potential -1000 mV, deposition time 150 s, and stirring rate 2000 rpm. The concentration of supporting electrolyte used was 300 µg/L NaCl and 1800 µg/L Na2SO4. The detection limit and sensitivity of the method using NaCl as supporting electrolyte were 0.1483 µg/L and 29.207 nA L/µg, respectively. The precision in the range of 1-5 µg/L of lead (II) was 1.01-6.37%. Lead (II) analysis voltammetrically using Na2SO4 as supporting electrolyte resulted in the analytical performance as follow: detection limit of 0.5498 µg/L, sensitivity of 8.037 nA L/µg, precision of 0.34-5.9 %. Analysis of lead (II) by stripping voltammetry using NaCl and Na2SO4 as supporting electrolyte resulted in recovery of 99.90 % (n=3) and 104.2 % (n=3), respectively. The presence of both NaCl and Na2SO4 slightly amplified the lead (II) current signal. ________________________________________GRAPHICAL ABSTRACT

Enhanced luminescence immunoassay: evaluation of a new, more sensitive thyrotropin assay.

1986 ◽  
Vol 32 (12) ◽  
pp. 2178-2183 ◽  
Author(s):  
R John ◽  
R Henley ◽  
D Chang ◽  
A M McGregor
Keyword(s):  
Detection Limit ◽  
Pregnant Women ◽  
Thyroid Function ◽  
Primary Hypothyroidism ◽  
Menopausal Women ◽  
Enhanced Luminescence ◽  
Thyroidal Status ◽  
Assay Precision ◽  
Post Menopausal

Abstract We measured thyrotropin (TSH) with an enhanced luminometric assay ("Amerlite"; Amersham International). The detection limit of the assay is 0.02 milli-int. unit/L. Within-assay precision was 6.7 and 7.8% at 3.77 and 12.1 milli-int units/L, respectively, and between-assay precision was almost identical, whether singleton or duplicate samples were assayed. TSH measured in 132 euthyroid subjects ranged from 0.06 to 4.13 milli-int. units/L (mean 1.52, SD 0.86). Similar concentrations were found in 20 healthy pregnant women and 19 of 20 healthy post-menopausal women (one of whom had undetectable TSH). In 17 patients with primary hypothyroidism, TSH concentrations ranged from 9.34 to greater than 200 milli-int. units/L; and in 53 of 59 patients with hyperthyroidism, TSH concentrations were undetectable, ranging in the remaining six from 0.03 to 0.06 milli-int. unit/L. Results for TSH in 28 patients stimulated with thyroliberin were consonant with the results of the thyroliberin test in 25 cases. Thus, for most patients, measurement of a basal TSH concentration evidently will predict their thyroidal status and also the response to thyroliberin, but a few will require additional tests of thyroid function.

Time-resolved immunofluorometric assay of total renin in plasma and follicular fluid

1994 ◽  
Vol 40 (1) ◽  
pp. 74-79 ◽  
Author(s):  
I Matinlauri ◽  
J U Eskola ◽  
M Aalto ◽  
P Koskinen ◽  
K Irjala
Keyword(s):  
Monoclonal Antibodies ◽  
Detection Limit ◽  
Human Plasma ◽  
Follicular Fluid ◽  
Reference Interval ◽  
Plasma Samples ◽  
Time Resolved ◽  
Analytical Recovery ◽  
Assay Precision ◽  
Follicular Fluids

Abstract We developed a new time-resolved immunofluorometric assay (TR-IFMA) using two monoclonal antibodies for the total renin measurement in human plasma and follicular fluid. No conversion of prorenin to renin was needed because the assay detected both renin and prorenin. The detection limit of the assay was 10 ng/L and the linear range was 10-25,000 ng/L. Within-assay precision (CV) was 15-8% at renin concentrations of 50-12,200 ng/L. Between-assay precision was 19-3% at concentrations of 100-18,000 ng/L. Analytical recovery of added renin was 85-104% (n = 5) in plasma samples and 104-119% (n = 3) in follicular fluids. For plasma, the reference interval was 78-262 ng/L in men (n = 44) and 36-226 ng/L in women (n = 43).

scholarly journals The determination of N-methylcarbamate pesticides using enzyme immunoassays with chemiluminescent detection

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S280-S282 ◽  
Author(s):  
B. Mičková ◽  
P. Rauch ◽  
A. Montoya ◽  
E. Ferri ◽  
F. Fini ◽  
...  
Keyword(s):  
Detection Limit ◽  
Matrix Effects ◽  
Colorimetric Detection ◽  
Fruit Juices ◽  
Analytical Performance ◽  
Experimental Comparison ◽  
Enzyme Immunoassays ◽  
Chemiluminescent Detection ◽  
Concentration Levels

In the present work, enzyme-linked immunosorbent assays (ELISAs) with chemiluminescent detection for the determination of carbofuran, carbaryl and methiocarb were developed and the analytical parameters of these assays were compared with those of ELISAs with colorimetric detection. The sensitivity of immunochemical methods was expressed as detection limit, linear working range, and I<sub>50</sub> value. In comparison with colorimetric ELISA, the ability of the chemiluminescent reagents to detect lower concentrations of HRP allowed to decrease the optimal antibody and conjugate concentrations and to reach better analytical parameters. The experimental comparison of the analytical performance of the ELISAs was carried out by analysing simply diluted fruit juices, spiked at different concentration levels with the above mentioned pesticides. Recovery values for both ELISAs were around 100% and no matrix effects were observed when fruit juices were diluted 1:20 or more.

scholarly journals Distinct differences in analytical performance of two commercially available assays for specific IgE to egg white and house dust mite allergens

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Komei Ito ◽  
Kazunori Tagami
Keyword(s):  
House Dust ◽  
House Dust Mite ◽  
Specific Ige ◽  
Egg White ◽  
Analytical Performance ◽  
Ige Antibodies ◽  
Ige Antibody ◽  
Allergen Components ◽  
Dust Mite ◽  
Human Sera

Abstract Background Measurements of allergen-specific IgE antibodies with different manufacturers’ assays show modest or poor agreement. This study compares analytical performance of specific IgE tests for whole allergen extracts and individual allergen components of two assay systems, IMMULITE and ImmunoCAP, using human sera as well as monoclonal antibodies. Methods Comparisons were performed for specific IgE to house dust mite (HDM, n = 44), egg white (EW, n = 36) and the allergen components rDer p 1, rDer p 2, nGal d 1, nGal d 2 and nGal d 4 in human sera and with monoclonal mouse/human chimeric IgE antibodies specific for the same allergen components. Competitive interference with IgE measurement was investigated using allergen-specific monoclonal IgG and IgG4 antibodies. Results Measurements of IgE to HDM and EW in serial dilutions of human sera revealed weaker dilution linearity with IMMULITE than with ImmunoCAP. Analysis of five different monoclonal IgE antibodies with total and specific IgE assays, expected to return similar levels, gave an average specific/total IgE ratio of 0.96 (range 0.71–1.14) with ImmunoCAP and 1.89 (range 0.76–2.85) with IMMULITE, indicating overestimation of specific IgE by IMMULITE. With the EW IgE tests of both assay systems, measurements of a chimeric anti-Gal d 2 IgE antibody were unaffected by a competing mouse IgG antibody. While the same was true for measurement of a chimeric anti-Der p 1 IgE antibody using the HDM test in ImmunoCAP, a suppression of measured concentrations by up to 42% was observed in IMMULITE. Similarly, measurement of HDM-specific IgE in human sera by ImmunoCAP was unaffected by a competing monoclonal anti-Der p 2 IgG4 antibody while IMMULITE displayed a reduction of HDM-specific IgE values by up to 30%. Conclusions In this evaluation of analytical performance of two widely used assay systems, ImmunoCAP showed higher accuracy in quantitation of specific IgE and greater resistance against competing allergen-specific non-IgE antibodies which may arise through natural or dietary exposure, or as a result of allergen immunotherapy treatment.

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