Comparison of Four Different Assays for Determination of Serum S-100B

2005 ◽  
Vol 20 (1) ◽  
pp. 34-42 ◽  
Author(s):  
L.H.M. Smit ◽  
C.M. Korse ◽  
J.M.G. Bonfrer
Keyword(s):  
Clinical Data ◽  
Reference Values ◽  
Method Comparison ◽  
Correlation Coefficients ◽  
Roc Curves ◽  
Reference Standard ◽  
Healthy Individuals ◽  
Coefficients Of Variation ◽  
Melanoma Patients

Background S-100B determination has been shown to be clinically useful in the management of melanoma patients. After the development of a test for determination of the isoforms S100-A1B and S100-BB in serum (S-100B), several sensitive assays for the detection of serum S-100B have become available. We compared four S-100B assays, two automated (LIAISON®Sangtec®100 and Elecsys®S100) and two manual ones (Sangtec®100 ELISA and CanAg S100 EIA), with respect to clinical data, reference values and correlation. Methods In a total of 280 samples from 155 melanoma patients and 98 healthy individuals S-100B values were measured simultaneously with the different assays. Results The inter and intra coefficients of variation were best for the automated assays. The functional sensitivity of both manual assays was 0.15 μg/L. Method comparison revealed satisfactory correlation coefficients of 0.9 or higher, but the slopes ranged from 0.29 to 3.36. Except for the Sangtec®100 ELISA, the linearity between the assays was acceptable. The overall sensitivity for melanoma ranged from 37% (Elecsys®S100) to 47% (LIAISON®Sangtec®100) and the sensitivity increased with stage. ROC curves showed the best accuracy for the LIAISON®Sangtec®100 assay. Conclusions All assays gave satisfactory results, but it is advisable to improve the performance of the manual assays for better sensitivity. Agreement about an international reference standard is needed.

scholarly journals Verification study of free light chains assays on reagent-optimized analysers

2019 ◽  
Vol 29 (3) ◽  
pp. 579-586
Author(s):  
Dragana Šegulja ◽  
Danica Matišić ◽  
Karmela Barišić ◽  
Dunja Rogić
Keyword(s):  
Method Comparison ◽  
Correlation Coefficients ◽  
Light Chains ◽  
Free Light Chains ◽  
Serum Samples ◽  
Three Samples ◽  
Coefficients Of Variation ◽  
Satisfactory Precision ◽  
Haematological Patients ◽  
Method Comparison Study

Introduction: Our aim was to compare analytical specifications of two assays (monoclonal vs. polyclonal) for free light chains (FLCs) quantification optimized for two different analytical platforms, nephelometer ProSpec (Siemens, Erlangen, Germany) and turbidimetric analyser Optilite (The Binding Site, Birmingham, UK). Materials and methods: The evaluation included verification of the precision, repeatability and reproducibility, estimation of accuracy and method comparison study with 37 serum samples of haematological patients. Kappa and lambda FLC were measured in each sample by both methods and kappa/lambda ratio was calculated. Results: Results show satisfactory precision of both methods with coefficients of variation for ProSpec of CVwr = 2.20% and CVbr = 3.44%, and for Optilite CVwr = 2.82% and CVbr = 4.15%. Estimated bias for FLC lambda was higher on the ProSpec analyser, but bias for FLC kappa was higher on the Optilite analyser. Correlation coefficients were 0.98; P < 0.001 for FLC kappa and 0.97; P < 0.001 for FLC lambda. Considering normal/pathological FLC ratio moderate agreement within assays was detected (κ = 0.621). When the results were categorized according to criteria for progressive disease, 4/37 (0.10) cases were differently classified. Lambda FLC values by Optilite in three samples with monoclonal FLC lambda were more than twelve times higher than by ProSpec. A 25% difference in FLC ratio was detected in 16/37 (0.43) and 50% difference in 13/37 (0.35) patients. Conclusions: All manufacturers’ precision claims could not be achieved in the verification study. The comparison of results to biological variations data showed that coefficients of variations are acceptable for both assays. The assays should not be used interchangeably in haematological patients.

scholarly journals Multicenter Evaluation of Five Assays for Myoglobin Determination

2000 ◽  
Vol 46 (10) ◽  
pp. 1631-1637 ◽  
Author(s):  
Martina Zaninotto ◽  
Franca Pagani ◽  
Sara Altinier ◽  
Paolo Amboni ◽  
Roberto Bonora ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Rheumatoid Factor ◽  
Reference Values ◽  
Multicenter Study ◽  
Method Comparison ◽  
Correlation Coefficients ◽  
Analytical Performance ◽  
Men And Women ◽  
Reference Limits

Abstract Background: Lacking assay standardization, different myoglobin methods may produce results that differ significantly. Methods: A multicenter study was carried out to compare the analytical performance of five commercially available assays for myoglobin measurement. Linearity, imprecision, interferences, and method comparison were studied according to NCCLS guidelines, whereas reference values were determined following IFCC recommendations. Results: The BNA and Opus showed relatively high imprecision (all but one total CV &gt;7.4%). Other assays showed lower CVs, but they varied among laboratories, particularly at a normal myoglobin concentration (Access, 6.0–11%; Hitachi, 3.8–5.8%; Stratus, 3.4–6.5%). Results were lower in anticoagulated samples on the Access, in heparin and citrate samples on the Stratus, and in citrate samples on the BNA and Opus, and increased in heparin and EDTA samples on the Hitachi. Use of separator gel produced results significantly lower (P &lt;0.001) on the Hitachi and higher (P = 0.016) on the Opus. Bilirubin, turbidity, and hemoglobin had no effect on evaluated methods, but rheumatoid factor affected the Access. In method comparisons, high correlation coefficients (≥0.98) were obtained. The Stratus gave higher results; however, the Access and BNA gave the lowest. The following upper reference limits (μg/L) for men and women, respectively, were obtained: Access, 70 and 52; BNA, 51 and 49; Hitachi, 67 and 58; Opus, 80 and 50; and Stratus, 86 and 63. Conclusion: The possibility of high imprecision and marked disagreement among commercial myoglobin assays should be carefully considered in clinical practice.

Radioimmunoassay and enzyme immunoassay compared for determination of digoxin.

1976 ◽  
Vol 22 (12) ◽  
pp. 2029-2031 ◽  
Author(s):  
L Sun ◽  
V Spiehler
Keyword(s):  
Enzyme Immunoassay ◽  
Correlation Coefficients ◽  
Coefficients Of Variation ◽  
Quantitative Results ◽  
High Control

Abstract Patients' sera were analyzed for digoxin by using two different radioimmunoassays and an enzyme immunoassay. Quantitative results obtained by enzyme immunoassay (I) were compared to results obtained on aliquots of the same sample by the radioimmunoassays (II and III). The correlation coefficients were: I vs. II 0.90, n=108; I vs. III 0.94, n=102; and II vs. III 0.95, n=158. Day-to-day precision (10 days) on a low control (1.3 mug/liter) and a high control 3.0 mg/liter), expressed as coefficients of variation, were: I, 13% and 7.8%, II, 4.0% and 4.7%; and III, 8.9% and 4.2%. Ten digoxin-supplemented samples (0-8 mug/liter) were analyzed by the three methods. Correlation coefficients were: supplemented sample vs. I, O.99; supplemented sample vs. II, 0.97; supplemented sample vs. III, 0.98.

Multicenter Evaluation of Commercially Available Methods for the Immunological Determination of Plasminogen Activator Inhibitor-1 (PAI-1)

1993 ◽  
Vol 70 (05) ◽  
pp. 858-863 ◽  
Author(s):  
P J Declerck ◽  
H Moreau ◽  
J Jespersen ◽  
J Gram ◽  
C Kluft
Keyword(s):  
Correlation Coefficients ◽  
Plasminogen Activator Inhibitor ◽  
Plasma Samples ◽  
Plasminogen Activator Inhibitor 1 ◽  
A Value ◽  
Normal Plasma ◽  
Coefficients Of Variation ◽  
A Minor ◽  
Pai 1

SummaryIn order to evaluate the comparability of data obtained with various available kits for the immunological determination of PAI-1 antigen in plasma and in order to investigate the underlying cause of observed differences, e. g. problems of specificity or of proper calibration of the provided standard, a multicenter study was organised in the framework of the Subcommittee of Fibrinolysis of the Scientific and Standardization Committee.Eight different plasma samples were distributed among 16 laboratories: a pooled normal plasma, NIBSC 87/512, PAI-1 antigen depleted plasma, PAI-1 depleted plasma supplemented with 59 ng/ml active PAI-1 and four different individual plasma samples. A considerable variation in absolute values is observed between the various kits, e.g. in pooled normal plasma a value is found ranging between 7.4 and 28 ng/ml. Harmonization of all data relative to the PAI-l-depleted plasma supplemented with an exact amount of active PAI-1 (59 ng/ml), followed by a statistical analysis using a two way analysis of variance, revealed that 6 out of 7 kits yielded values that were not significantly different with coefficients of variation around 30%. Correlations between the values obtained with these kits yielded slopes between 0.75 and 1.44 with correlation coefficients between 0.973 and 0.999. Values obtained with one kit appeared to be significantly different (even after harmonization) from the other kits (p <0.001 to p <0.05). Comparison of PAI-1 antigen with the PAI activity values in the analysed samples suggests that one kit may deal with a problem of a difference in reactivity between active and latent PAI-1.In conclusion 6 different kits yield results that, only after harmonization, are comparable and do correlate very well. Thus proper calibration of the provided standards may solve the majority of the problems observed with PAI-1 antigen kits. Differential specificity towards different conformational forms of PAI-1, as a consequence of the use of different monoclonal antibodies, is a minor, but a potential problem, that needs to be considered when comparing data obtained with various methods.

New System for Automated Extraction and Simultaneous Determination of Serum Cholesterol and Triglycerides

1975 ◽  
Vol 21 (10) ◽  
pp. 1430-1436 ◽  
Author(s):  
Dorothy F Wease ◽  
Eli S Espinosa ◽  
Yvonne J Anderson
Keyword(s):  
Simultaneous Determination ◽  
Lipid Extraction ◽  
Small Animal ◽  
Correlation Coefficients ◽  
Sample Volume ◽  
Small Sample ◽  
Automated System ◽  
Coefficients Of Variation ◽  
Precision Time

Abstract We describe an automated system for serum lipid extraction and simultaneous determination of cholesterol and triglycerides, with use of continuous-flow equipment. A sample volume of 100 µl of serum is required, and samples are processed at the rate of 20 per hour, which may be increased with slight loss in precision. Time from sample pickup to recorder readout is about 25 min. The system makes use of established colorimetric reactions, and the values obtained agree with ranges currently reported in the literature. Correlation coefficients for results of the automated and manual methods were 0.98 for cholesterol and 0.99 for triglycerides, and the day-to-day coefficients of variation were 1.8% for cholesterol (1 SD = 34 mg/liter) and 3.4% for triglycerides (1 SD = 37 mg/liter). The small sample volume, precision, accuracy, speed, and comparative economy of reagents make this system particularly suitable for multiphasic screening, pediatrics, and small-animal research.

Simple Method for Determination of Dietary Fiber in Frozen Foods

1993 ◽  
Vol 76 (5) ◽  
pp. 1014-1016 ◽  
Author(s):  
Sami M Al-Hasani ◽  
Jan Hlavac ◽  
Mark A Huntsman
Keyword(s):  
Dietary Fiber ◽  
Phosphate Buffer ◽  
Pancreatic Enzyme ◽  
Correlation Coefficients ◽  
Single Component ◽  
Frozen Foods ◽  
Simple Method ◽  
Coefficients Of Variation

Abstract A simple method was developed for the determination of dietary fiber in multicomponent foods. The method involves dispersing the sample into pH 7.4 phosphate buffer and adding bile and pancreatic enzyme as described. Results were comparable to AOAC methods with correlation coefficients of 86% for multicomponent dinners and 89% for breakfast foods. Coefficients of variation ranged from 7.4 to 20.0% for multicomponent foods and 1.0 to 3.6% for single component foods. In addition, blind duplicate samples had a correlation of 0.99. The described method required less time, labor, and manipulation than AOAC methods

Ves-Matic CUBE 200: is modified Westergren method for erythrocyte sedimentation rate a valid alternative to the gold standard?

2019 ◽  
Vol 72 (10) ◽  
pp. 716-719
Author(s):  
Ivana Lapić ◽  
Elisa Piva ◽  
Federica Spolaore ◽  
Giulia Musso ◽  
Francesca Tosato ◽  
...  
Keyword(s):  
Erythrocyte Sedimentation Rate ◽  
Sedimentation Rate ◽  
Gold Standard ◽  
Method Comparison ◽  
Erythrocyte Sedimentation ◽  
Small Constant ◽  
Coefficients Of Variation ◽  
Key Points ◽  
Automated Determination

Ves-Matic CUBE 200 is an automated erythrocyte sedimentation rate (ESR) analyser based on the modified Westergren principle of measurement. In this study, we aimed to assess its analytical performance following the key points addressed by the International Council for Standardization in Haematology and the comparability with the gold standard Westergren method. Comparison of the two methods yielded a correlation coefficient of 0.852, no significant bias and a small constant difference between compared results. Intrarun coefficients of variation (CV) ranged from 2.2% to 22.2%, the higher being for lower ESR values, while inter-run CVs were 19.7% for the normal range and 3.0% for the abnormal range. This study proved the analytical validity of the Ves-Matic CUBE 200 and its high comparability with the Westergren method, showing obvious improvements in the technology applied for automated determination of ESR and a valuable step forward in standardisation of ESR methods.

Determination of Methyl 2-Benzimidazolecarbamate in Bulk Fruit Juice Concentrates by Competitive-Inhibition Enzyme Immunoassay

1994 ◽  
Vol 77 (5) ◽  
pp. 1237-1243 ◽  
Author(s):  
Rodney J Bushway ◽  
Barbara E S Young ◽  
Lance R Paradis ◽  
Lewis B Perkins ◽  
Susan K Martin ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Fruit Juice ◽  
Dynamic Range ◽  
Competitive Inhibition ◽  
Correlation Coefficients ◽  
Total Sample ◽  
Coefficients Of Variation ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic

Abstract A polyclonal enzyme immunoassay (EIA) was used to quantitate methyl 2-benzimidazolecarbamate (MBC or carbendazim), a degradation product of benomyl, in bulk fruit juice concentrates. These concentrates are used by industrial producers to prepare juice or juice concentrates sold in supermarkets. Total sample analysis time was less than 18 min without cleanup or 35 min with cleanup. As many as 8 samples can be analyzed simultaneously, with a limit of quantitation of 10 ppb. The assay’s dynamic range ran from 0.5 to 20 ppb MBC but was best from 0.5 to 10 ppb. Intra-assay coefficients of variation (CVs) varied from 4.0 to 13% for standards and from 4.1 to 26% for samples. Inter-assay CVs varied from 4.5 to 47% for standards and 5.6 to 22% for samples. Average recovery of several juice concentrates spiked at 10 to 290 ppb was 97%. A total of 140 juice concentrates comprising 20 different kinds of juice were analyzed by 2 EIA methods and one liquid chromatographic (LC) procedure. MBC-positive samples gave the following correlation coefficients: 0.954 for EIA without cleanup vs LC, 0.956 for EIA with cleanup vs LC, and 0.978 for EIA with cleanup vs EIA without cleanup. MBC concentrations in MBC-positive juice samples ranged from 5 to 2960 ppb.

Cortisol production rate determined by radio gas-chromatography.

1977 ◽  
Vol 23 (3) ◽  
pp. 518-521 ◽  
Author(s):  
H J Derks ◽  
F A Muskiet ◽  
B G Wolthers ◽  
J H Thijssen ◽  
N M Drayer
Keyword(s):  
Production Rate ◽  
Chromatographic Method ◽  
Correlation Coefficients ◽  
Urinary Cortisol ◽  
Coefficients Of Variation ◽  
Specific Activities ◽  
Gas Chromatographic Method ◽  
Layer Chromatography ◽  
Cortisol Metabolites

Abstract We describe a ratio gas-chromatographic method for determination of cortisol production rate by measuring the isotope dilution of urinary cortisol metabolites. The method was calibrated by analyzing [3H]tetrahydrocortisol and [3H]tetrahydrocortisone of known specific activities. Results are reasonably well reproducible, the coefficients of variation ranging from 8-15% of allotetrahydrocortisol/tetrahydrocortisol and from 9-19% for tetrahydrocortisone. Correlation coefficients were 0.966 and 0.998 for tetrahydrocortisone and allotetrahydrocortisol/tetrahydrocortisol, respectively, when the method was compared with a method involving thin-layer chromatography and colorimetry. Only one chromatographic step is needed for both purification and quantitation, thus time and effort are saved.

Monitoring of Heparin and Low Molecular Weight Heparin with Capillary and Venous Whole Blood

1988 ◽  
Vol 60 (03) ◽  
pp. 377-381 ◽  
Author(s):  
J Harenberg ◽  
Ch Giese ◽  
C E Dempfle ◽  
G Stehle ◽  
D L Heene
Keyword(s):  
Whole Blood ◽  
Normal Values ◽  
Correlation Coefficients ◽  
Blood Samples ◽  
Coefficients Of Variation ◽  
Coagulation Tests ◽  
Coagulation Assay ◽  
Antifactor Xa ◽  
Whole Blood Samples

SummaryA method for determination of antifactor Xa-like activity in capillary whole blood obtained from the fingertip is described, which employs the Heptest coagulation assay. Values obtained with capillary whole blood are compared to values of corresponding plasma and venous whole blood samples. Normal values in plasma, venous whole blood, and capillary blood from the fingertip were 17.1 ± 2.1, 10.0 ± 1.3 and 10.4 ± 1.3 sec, respectively. The intraindividual coefficients of variations range from 0.4 to 1.8% in all assays. The day to day coefficient of variation of normal values ranged between 0.8 and 2.0% for all assays. The within assay coefficients of variation ranged from 3.0 to 7.7% for whole blood samples and from 1.5 to 2.2% for plasma samples after addition of no, 0.2 or 1.0 units of normal or LMW heparin to the samples. After administration of heparin or LMW heparin in healthy persons the coagulation values of the different coagulation assay systems displayed coefficients of correlation betweell r = 0.87 and r = 0.95. Correlation coefficients between the coagulation tests and the S 2222 chromogenic substrate method ranged from r = 0.77 to r = 0.92. In patients, who received LMW heparin for prophylaxis of thromboembolism the coagulation assay correlated between r = 0.78 and 0.92. The coagulation assays and the S 2222 method displayed coefficients of correlation between r = 0.74 and r = 0.83. The data indicate that Heptest sensitively measures antifactor Xa-like activity in capillary whole blood as well as venous whole blood samples containing low quantities of heparin or LMW heparin.

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