[The quantitative determination of serum haptoglobin by the peroxidase activation method and by radial immunodiffusion. A comparison of methods (author's transl)].
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Adult↗
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Results for “method comparison”
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[Maternal lactation as a contraception method? 3. Comparison of maternal lactation with current methods of contraception].
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Amenorrhea↗
[Further observations on a simplified method for the execution of antibiograms. Comparison with method of broth dilution (author's transl)].
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Anti-Bacterial Agents↗
Comparison of the reflectance method (Reflotron reflectance photometer) with the absorbance method (automatic analysers) for the determination of cholesterol.
The European Atherosclerosis Society (1) and the Expert Panel of the US National Cholesterol Education Program (2) have issued detailed guide values for recognition and management of hyperlipidaemia in adults. In these guidelines, the diagnosis of dyslipidaemia based on the measurements of total cholesterol, triacylglycerols, HDL and LDL cholesterol plays an important role. A prerequisite for the desired success of interventive measures is the reliability of the analytical data. The aim of this study was to investigate the precision and accuracy of Reflotron Cholesterol, a method based on the dry chemistry principle. Accuracy was assessed by establishing the correlation with the standardized automated methods used in routine lipid diagnosis. In addition, it was also examined whether the Reflotron Cholesterol results in plasma and blood are comparable. The Reflotron cholesterol (sample: blood) showed a good correlation with the CHOD/PAP method on a Hitachi 737 instrument (sample: plasma). The median value of the differences of the test results was -0.4%. Similarly, the method comparison of Reflotron Cholesterol (sample: blood) versus CHOD/PAP method on a SMAC instrument (sample: plasma) showed that Reflotron produces slightly (1.8%) higher results. The Reflotron Cholesterol values obtained from blood samples were slightly lower than those from plasma samples (median value of the differences: -2.2%). The results suggest that for routine purposes Reflotron Cholesterol provides results which are in good agreement with those obtained by standardized wet chemistry methods.
Autoanalysis↗
Motor threshold in transcranial magnetic stimulation: comparison of three estimation methods.
AIMS: Motor threshold (MT) is an important parameter for the practice of transcranial magnetic stimulation. Our goal was to compare three methods to estimate MT in a clinical setting. METHODS: Comparison of three MT estimation algorithms: 1) the Rossini-Rothwell method consists in lowering stimulus intensity until only five positive responses out of 10 trials are recorded, defining MT; 2) the Mills-Nithi method considers the MT as the mean of an upper threshold (10 positive out of 10 trials) and a lower threshold (0 out of 10 trials); 3) the supervised parametric method estimates the MT by fitting (mathematically and graphically) a sigmoid function on raw data obtained by stimulation at variable intensities. Six MT estimations (two per method) were recorded in a single session in 10 healthy subjects. RESULTS: The within-subject variation of MT (expressed as % of the mean MT+/-standard deviation) during a single session was of 8.5+/-7.2% for the Rossini-Rothwell method, 8.7+/-5.7% for the Mills-Nithi method and 9.5+/-4.0% for the supervised parametric method. No significant differences in variability of MT estimation were found between the methods, but the Rossini-Rothwell method was significantly shorter (half the number of stimuli compared to the two other methods). CONCLUSION: In our setting, Rossini-Rothwell method was superior to the two other methods. The variability of MT estimation measured in our study is important, yet acceptable for clinical applications. However, this variability can be a source of considerable errors in excitability studies and should be a focus of future research.
Adult↗
Comparison of three automated methods of serum tirglyceride analysis.
Two new automated methods for serum triglyceride analysis are described and compared with each other and with an established chemical method. They are a chemical method requiring no glycerol blank correction and a commercially available fully enzymatic method requiring no prior lipid extraction. Both methods had higher quality control precision and faster sampling rates than the established method. Comparison of duplicate analyses of a random series of serum samples by all three methods gave a closer correlation between the new methods than between either and the conventional method.
Adult↗
Performance characteristics of seven automated CA 15-3 assays.
Measurements of serum cancer antigen (CA) 15-3 are used to monitor tumor recurrence and treatment of advanced disease. We evaluated the performance characteristics, including limit of detection, linearity, method comparison, and reference intervals, of 7 automated methods for CA 15-3, including the Access 2 (Beckman Coulter, Brea, CA), ADVIA Centaur (Bayer Diagnostics, Tarrytown, NY), ARCHITECT i2000 and AxSYM (Abbott Diagnostics, Abbott Park, IL), Elecsys 2010 (Roche Diagnostics, Indianapolis, IN), IMMULITE 2000 (Diagnostic Products, Los Angeles, CA), and VITROS ECi (Ortho Clinical Diagnostics, Raritan, NJ) assays. The limit of detection for each assay was less than 1.0 kU/L. The maximum deviation for the target values for linearity samples was less than 10% for all methods. Method comparison studies revealed large differences for some individual samples. Overall slopes ranged from 0.50 to 1.48, and correlation coefficients were 0.90 to 0.96 when the ADVIA Centaur was the comparison method. The 97.5 percentile upper reference limit ranged from 23.3 to 51.7 kU/L. Additional standardization efforts are needed, and the availability of reference material is required. Substantial intermethod differences exist for some patient samples, indicating that redetermining the baseline is required when changing methods.
Biomarkers, Tumor↗
Determination of urinary protein fractions. A comparison with different electrophoretic methods and quantitatively determined protein concentrations.
The second morning urine of 207 patients with various renal diseases was examined. After testing the urine with the Combur-9-RL((R)) dip strip, the concentrations of total protein, creatinine, albumin, alpha-1-microglobulin, immunoglobulin G and transferrin were determined. The urinary protein fractions were measured in parallel with the electrophoresis kits: Hydragel-Proteinuria (sebia GmbH, Fulda); Protur-HiSi (Beckman Coulter GmbH, Krefeld); SPE-II (Beckman Coulter) and the protein concentrations were calculated. The method comparison was based on the agreement of the ascertained types of proteinuria, and on comparison of the electrophoretically obtained albumin protein concentrations with the automated concentration results. It could be shown that urine electrophoresis is a reliable analytic method for the diagnosis of proteinurias. A good agreement and significant correlations were found between single protein determination and urinary electrophoresis. A diagnostic strategy that combines electrophoresis, single protein determination and immunofixation is useful for the diagnosis and differentiation of proteinuria.
Albuminuria↗
Protein determination: a comparison of several methods.
A comparison of four methods for the determination of total proteins is presented from the following points of view: - sensitivity; - specificity; - amount of work, chemicals, time and equipment needed for the performance of the determination. The following tests have been examined; Tombs' (absorbancy at 210 nm); Waddell's (difference in absorbancy between 215 and 225 nm); Warburg's (absorbancy at 280 nm); Lowry's (absorbancy at 500 nm after the reaction with phenol reagent). The authors recommend Tombs' method for its outstanding sensitivity, specificity and simplicity as the best of the four.
Animals↗
Direct monitoring of glycohemoglobin A1c in the blood samples of diabetic patients by capillary electrophoresis. Comparison with an immunoassay method.
The capillary electrophoresis (CE) study was focused on quantifying glycohemoglobin A1c, HbA1c, in whole blood samples of patients suffering diabetes mellitus. The results showed that dynamic polyionic coating of the capillary made the method very reproducible. The precision evaluation, method comparison and bias estimation in CE were performed during 20 days with patient blood samples and with four control samples. The influence of the storage time and temperature on the glycohemoglobin levels were also tested. High resolution in CE could be used to show evidences of the ageing of the samples stored at -70 degrees C. The results showed that the ageing peak was not originated from HbA1c, because it did not affect the HbA1c level which was in balance with the results of fresh samples measured with immunoassay. The HbA1c % values of blood samples of 105 patients measured with the CE technique varied between 3.6 and 11.8 and they were approximately 2-3% lower than measured with immunoassay. The correlation (R2) of CE results with immunoassay and HPLC results were 0.962 and 0.781, respectively.
Diabetes Mellitus↗
Comparison of biochemical simulations using integrators derived from "Adomian" decomposition with traditional numerical methods.
Comparisons are made between some traditional numerical integrators and integration using "Adomian" power series solutions to the ordinary differential equations. These are initial investigations to determine the viability of their application to the simulation of large complex metabolic pathways. A small set of test equations was employed to represent the types of problems encountered in biochemical applications. It was found that the "Adomian" method is as accurate as the numerical methods and, for 'nonstiff' equations or for small simulation times, the "Adomian" method is often more efficient. The results suggest that it may be worthwhile refining this method for biochemical simulations for situations where the traditional numerical methods fail.
Computer Simulation↗
Resonance frequency analysis and damping capacity assessment. Part I: an in vitro study on measurement reliability and a method of comparison in the determination of primary dental implant stability.
OBJECTIVES: The aims of this in vitro study were to evaluate reliability of the Osstell and Periotest devices in the assessment of implant stability and to perform a method comparison. MATERIAL AND METHODS: Commercial dental implants were inserted into bovine rib segments of different anatomical origins and densities. Repeated measurements were performed, varying (a) the torque-in force of the devices' attachment screw (the Osstell transducer and the ball attachment, insert for the Periotest device), (b) the insertion site bone quality, and (c) the thread exposure in simulated peri-implant bone defects. RESULTS: Both methods were comparably reliable and showed a strong association to each other in the classification of implant stability. As opposed to torque-forced screw attachment, the variations in bone composition, differences in inter-implant stability of adjacent implants, and peri-implant bone reduction were statistically significant for both methods. CONCLUSIONS: Both non-invasive diagnostic devices seem to be useful in the long-term follow-up of implant integration.
Animals↗
Evaluation of a semi-automated blood urea nitrogen analyzer.
We compared results for urea concentrations in plasma and serum as measured with the Kimble Blood Urea Nitrogen Analyzer method as the test method with those determined by continuous-flow analysis (AutoAnalyzer 1 method) as the comparison method. We evaluated accuracy and precision for patients' samples, National Bureau of Standards Standard Reference Material, College of American Pathologists Survey Validated Reference Materials, and College of American Pathologists Quality Assurance Service control materials. We found the test method to be more accurate and precise than the comparison method.
Autoanalysis↗
Cutaneous leishmaniasis in Guatemala: comparison of diagnostic methods.
A comparison was made of methods used to diagnose suspected cutaneous leishmaniasis in Guatemala. The most sensitive method was a combination of thin smears made from superficial scrapings of the ulcers and inoculation of culture medium with either aspirates or scrapings. The diagnosis was confirmed in 252 (70%) of 362 patients. Ability to cultivate Leishmania was correlated with the concentration of amastigotes seen on thin smears. Leishmania were cultured in 42 (27%) of 153 patients with no amastigotes found in 400 oil-immersion fields and in 174 (83%) of 209 patients with at least 1 amastigote. No difference in diagnostic outcome was found when we compared smears or cultures taken from the center or the border of the ulcer or from an incision made tangential from the ulcer. We found no difference when we compared smears obtained with scalpels, capillary tubes, or dental broaches. The use of scrub brushes soaked in iodine neither decreased the rate of culturing parasites nor decreased contamination rates.
Animals↗
Rod and cone psychophysics and electroretinography: methods for comparison in retinal degenerations.
Methods have been developed to compare full field rod and cone electroretinograms with results of rod and cone static perimetric measurements across the visual field. In a limited number of patients with retinal degeneration, including two subtypes of retinitis pigmentosa, there were close relationships between electroretinographic and psychophysical parameters. Maximum b-wave amplitude and visual field area were highly correlated, as were electroretinographic and perimetric measures of sensitivity loss. Future application of the methods to large numbers of patients with typical retinitis pigmentosa may help elucidate different mechanisms of retinal degeneration.
Adult↗
Determination of dithiocarbamate pesticides in occupational hygiene sampling devices using the isooctane method and comparison with an automatic thermal desorption (ATD) method.
Two new methods for the determination of dithiocarbamate pesticides in occupational hygiene sampling devices are described. Dithiocarbamate spiked occupational hygiene sampling devices, consisting of glass fibre (GF/A) filters, cotton pads, cotton gloves and disposable overalls, were reduced under acidic conditions and the CS2 evolved as a decomposition product was extracted into isooctane. The isooctane was then analysed using gas chromatography with mass spectrometry, for CS2, which provided a quantitative result for dithiocarbamates. Recoveries obtained were generally within a 70-110% range and reproducibilities better than 15% RSD were typically achieved. The method has been successfully applied to samples collected during occupational exposure surveys. A second method employing automatic thermal desorption-gas chromatography-mass spectrometry (ATD-GC-MS) has also been developed and applied to the direct analysis of GF/A (airborne) samples. The method relies on the thermal degradation of dithiocarbamates to release CS2, which is used to quantify the analytes. Thiram spiked GF/A filters gave an average recovery of 107% with an RSD of 4%. The performance of the two analytical methods were directly compared by analysing sub-portions of GF/A filters collected during a survey to evaluate occupational exposures to thiram during seed treatment operations. Both methods performed well for the analysis of airborne (GF/A) samples and produced results in good agreement. ATD-GC-MS is the preferred method for studies involving GF/A (airborne) samples only. Because of the wider applicability of the isooctane method for other sampling devices, it is the preferred choice when carrying out surveys which require a dermal as well as respirable exposure assessment.
Carbamates↗
Estimation of the absolute thyroid uptake of stable 127-I using a simplified method and comparison of the results with two classic methods.
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Adult↗
[Transabdominal prostatic sonography and bladder neck-colliculus distance measurement for preoperative determination of prostatic weight: 2 methods in comparison].
The two current methods to evaluate the weight of prostatic gland preoperatively, transabdominal ultrasound and measurement of bladder neck-colliculus distance in cystoscopy, are compared in 106 patients. The correlation of these methods with the real weight and the correctness of a preoperative division in a weight of more or less than 60 g as a border line between TUR and prostatectomy are described and discussed.
Aged↗