A Comparative Study of Free Thyroxine Estimations

Two commercial methods (Immophase, Corning and FT4, Lepetit) for the measurement of free thyroxine (FT4) in serum have been experimentally evaluated. Ease of handling and rapidity were satisfactory. Precision profiles showed intra-assay coefficients of variation not exceeding 5% over the entire measurement range (0–70 pmol/l) for both methods. Interassay coefficients of variation were below 8%. Assay results of both methods correlated well with those obtained with a symmetric dialysis method, with correlation coefficients of 0·95 for the Immophase and 0·93 for the Lepetit method and slopes not significantly different from unity. Comparison with this reference method did not give any indication of serious methodological error in either of the kits in spite of theoretical doubts with regard to one of them.

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Quantitative Fluorodensitometric Measurement of Aflatoxin B1 with a Flying-Spot Densitometer. II. Comparative Study of B1 Measurements in Spiked and Naturally Contaminated Peanut Products

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/55.6.1310 ◽

1972 ◽

Vol 55 (6) ◽

pp. 1310-1315

Author(s):

P R Beljaars ◽

F H M Fabry ◽

M M A Pickott ◽

M J Peeters

Keyword(s):

Comparative Study ◽

Silica Gel ◽

Aflatoxin B1 ◽

Peanut Butter ◽

Reference Method ◽

Amyl Alcohol ◽

The Other ◽

Coefficients Of Variation ◽

Tlc Plates ◽

Flying Spot

Abstract Peanut butter extracts and samples spiked with 5-40 μg anatoxin B1/kg were analyzed, together with naturally contaminated peanut products, by 3 extraction procedures: the official Dutch method (KB), he Liem et al. method (methanol), and the IUPAC method. The last procedure was selected as a reference method, since it has international application. KB extracts were separated on silica gel G plates with a mixture of chloroform-acetone (90 + 10), whereas IUPAC extracts were separated similarly on MN-G-HR plates. Methanol extracts were resolved on silica gel II plates, using chloroform-trichloroethylene-n-amyl alcohol-formic acid (80 + 15 + 4 + 1) as the developing solvent. After development, plates were scanned with a reflectance flying-spot densitometer. With such techniques, average recoveries for spiked peanut butter extracts ranged from 99 to 105%, with variation values of 11-12%. Recovery values of 69% (KB method) and 84% (methanol and IUPAC methods) were obtained for spiked peanut butter samples. Coefficients of variation ranged from 13 to 15% for fluorodensitometric measurements. Innaturally contaminated peanuts and peanut products , precision values were 13.6% for fluorodensitometric measurements compared to 36% for visual estimations . Both the methanol and IUPAC methods yield extracts suitable for densitometric analysis after spotting on TLC plates; the analytical results obtained are comparable. Extracts from the KB method contained more interfering fluorescent material than the other 2 methods

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

Biochemia Medica ◽

10.11613/bm.2019.030709 ◽

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.

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Evaluation of free and total L-thyroxine in serum by a commercial procedure.

Clinical Chemistry ◽

10.1093/clinchem/27.1.149 ◽

1981 ◽

Vol 27 (1) ◽

pp. 149-152 ◽

Cited By ~ 3

Author(s):

M J Obregon ◽

A Kurtz ◽

R Ekins ◽

G Morreale de Escobar

Keyword(s):

Pregnant Women ◽

Plasma Proteins ◽

Diagnostic Value ◽

Free Thyroxine ◽

Total Thyroxine ◽

Dialysis Method ◽

Hypothyroid Patients ◽

Hyperthyroid Patients ◽

Normal Controls

Abstract We assessed a commercial kit (Corning Medical) for "free" and total thyroxine determination, results being compared to those obtained by the Ekins and Ellis dialysis method (free thyroxine) and the method of Weeke and Orskov (total thyroxine). The kit procedure permits determination of both free and total thyroxine within 4 to 5 h, and the combined results may disclose changes in binding to plasma proteins that would be missed if only free thyroxine were determined. With both free-thyroxine methods, the values distinguished hyperthyroid patients from normal controls and pregnant women with 100% accuracy, but there was some overlap between hypothyroid patients and controls. Absolute values with the kit procedure often exceed those obtained by dialysis, especially for hypothyroid patients and pregnant women. We conclude that the kit may be of as much diagnostic value as the dialysis method if the limitations regarding absolute values are kept in mind and the test is not used as a substitute for thyrotropin determinations in cases of suspected hypothyroidism.

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Referencing laser and ultrasonic height measurements of barleycultivars by using a herbometre as standard

Crop and Pasture Science ◽

10.1071/cp16238 ◽

2016 ◽

Vol 67 (12) ◽

pp. 1215 ◽

Cited By ~ 10

Author(s):

Gero Barmeier ◽

Bodo Mistele ◽

Urs Schmidhalter

Keyword(s):

Plant Height ◽

Spring Barley ◽

Operating Time ◽

Reference Method ◽

Fold Increase ◽

Barley Cultivars ◽

Coefficients Of Variation ◽

Field Phenotyping ◽

High Throughput Phenotyping ◽

Distance Sensor

Assessment of plant height is an important factor for agronomic and breeder decisions; however, current field phenotyping, such as visual scoring or using a ruler, is time consuming, labour intensive, costly and subjective. For agronomists and plant breeders, the most common method used to measure plant height is still a meter stick. In a 3-year study, we have adopted a herbometre similar to a rising plate meter as a reference method to obtain the weighted plant height of barley cultivars and to evaluate vehicle-based ultrasonic and laser distance sensors. Sets of 30 spring barley cultivars and 14 and 60 winter barley cultivars were tested in 2013, 2014 and 2015, respectively. The herbometre was well suited as a reference method allowing for an increased area and was easy to handle. The herbometre measurements within a plot showed very low coefficients of variation. Good and close relationships (R2 = 0.59, 0.76, 0.80) between the herbometre and the ultrasonic distance sensor measurements were observed in the years 2013, 2014 and 2015, respectively, demonstrating also increased values of heritability. Hence, both sensors were able to differentiate among barley cultivars in standard breeding trials. For the sensors, we observed a 4-fold faster operating time and 6-fold increase of measurement points compared with the herbometre measurement. Based on these results, we conclude that distance sensors represent a powerful and economical high-throughput phenotyping tool for breeders and plant scientists to estimate plant height and to differentiate cultivars for agronomic decisions and breeding activities potentially being also applicable in other small grain cereals with dense crop stands. Particularly, ultrasonic distance sensors may reflect an agronomically and physiologically relevant plant height information.

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HemoCue against Coulter LH-750 in the estimation of hemoglobin levels of blood donors in mobile collection settings: a comparative study

Medical Journal of Indonesia ◽

10.13181/mji.v27i4.2635 ◽

2018 ◽

Vol 27 (4) ◽

pp. 250-5

Author(s):

Sultan A.M. Saghir ◽

Amer A. Almaiman ◽

Aishah K.A. Shatar ◽

Norris Naim ◽

Huda S. Baqir

Keyword(s):

Blood Donors ◽

Reference Method ◽

Cross Sectional Study ◽

Outpatient Setting ◽

Concordance Correlation ◽

Cross Sectional ◽

New Device ◽

Coefficients Of Variation ◽

Significant Difference

Background: The fast and outpatient setting for a determination of the hemoglobin (Hb) level is a well-recognized prerequisite to detect anemia in blood donors. This study aimed to evaluate the performance of the HemoCue methods (HemoCue B-Hb and HemoCue-301) against Coulter LH-750 as a reference method for Hb determination.Methods: This study was an experimental cross-sectional study. It includes 455 blood samples that were collected from volunteer blood donors between January 15, 2010 and February 15, 2011. The performance of the three methods and their comparisons were assessed using the analysis of coefficients of variation (CV), linear regression, and mean difference. Correlation coefficient and Bland–Altman plots were drawn to compare the two HemoCue measurements and the automated cell analyzer against each other and to evaluate their results. The Hb concentrations were compared using the concordance correlation coefficient.Results: The findings exhibited that the CV for the three methods Coulter LH-750, HemoCue B-Hb, and HemoCue-301 were 0.60%, 0.72%, and 0.92%, respectively. A statistically significant difference was observed between the means of the Hb measurements for the three methods (p<0.001). The HemoCue B-Hb and HemoCue-301 methods showed the best agreement, and the Coulter LH-750 method gave a lower Hb value compared with the two HemoCue methods. The results showed a positive correlation of HemoCue Hb results compared with the reference method.Conclusion: All three methods provide a good agreement for Hb determination. The new device HemoCue-301 was found to be more accurate compared with HemoCue B-Hb and Coulter LH-750.

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Genetic variability of rye-xenic-hybrid traits

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1996.050 ◽

2014 ◽

Vol 65 (3-4) ◽

pp. 329-333 ◽

Cited By ~ 1

Author(s):

Lechosław Grochowski ◽

Jan Kaczmarek ◽

Władysław Kadłubiec ◽

Henryk Bujak

Keyword(s):

Genetic Diversity ◽

Genetic Variability ◽

Plant Height ◽

Combining Ability ◽

Field Experiments ◽

Correlation Coefficients ◽

Winter Rye ◽

Arithmetic Means ◽

Coefficients Of Variation ◽

Standard Cultivar

In field experiments performed in two localities (Smolice, Wrocław) 18 xenic hybrids of winter rye, two testers and standard cultivar Dańkowskie Złote, were analysed. The objects of detailed evaluations were 11 traits. For six of them arithmetic means (x), standard deviations (S), coefficients of variation (cv), coefficients of genetic diversity (h<sup>2</sup>), correlation coefficients were calculated. Moreover, analyses of variance were carried out and the effects of general (GCA) and specific (SCA) combining ability were estimated. The existence of quantitative xenia in hybrids was confirmed. It was shown that xenic hybrids, in respect to most of the analysed traits, were insignificantly inferior to the testers and the standard cultivar. However, the decrease of plant height has shown to be significant and a tendency to higher yield was observed.

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3D Biometrics for Hindfoot Alignment Using Weightbearing Computed Tomography

Foot & Ankle International ◽

10.1177/1071100719835492 ◽

2019 ◽

Vol 40 (6) ◽

pp. 720-726 ◽

Cited By ~ 24

Author(s):

Jian Zhong Zhang ◽

François Lintz ◽

Alessio Bernasconi ◽

Shu Zhang ◽

Keyword(s):

Computed Tomography ◽

Comparative Study ◽

Interobserver Reliability ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Level Of Evidence ◽

Hindfoot Alignment ◽

Mean Values ◽

Intraclass Correlation Coefficients ◽

Prospective Comparative Study

Background: Weightbearing computed tomography (WBCT) is a useful tool for the assessment of hindfoot alignment (HA). Foot ankle offset (FAO) is a recently introduced parameter, determined from WBCT images using semiautomatic software. The aim of this study was to determine the clinical relevance and reproducibility of FAO for the evaluation of HA. Methods: A prospective comparative study was performed on consecutive patients requiring bilateral WBCT between September 2017 and April 2018. Based on the clinical assessment of HA, patients were divided into 3 groups: (1) normal alignment group (G1), (2) valgus (G2), and (3) varus (G3). FAO and long axial view (HACT) were measured on WBCT images, and the groups were compared. The reproducibility of FAO and HACT was determined through intraclass correlation coefficients (ICCs). Regression analysis was performed to investigate the correlation between the 2 methods. Overall, 249 feet (126 patients) were included (G1 = 115, G2 = 78, and G3 = 56 feet). Results: The mean values for FAO and HACT were 1.2% ± 2.8% and 3.9 ± 3.1, respectively, in G1; 8.1% ± 3.7% and 9.7 ± 4.9 in G2; and −6.6% ± 4.8% and −8.2 ± 6.6 in G3. Intra- and interobserver reliability was 0.987 and 0.988 for FAO and 0.949 and 0.949 for HACT, respectively. There was a good linear correlation between HACT and FAO ( R2 = 0.744), with a regression slope of 1.064. Conclusions: WBCT was a useful method for the characterization of HA. FAO was reproducible and correlated well with physical examination. Level of Evidence: Level II, prospective comparative study.

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Reproducibility of Fixed-luminance and Multi-luminance Flicker Electroretinography in Patients With Diabetic Retinopathy Using an Office-based Testing Paradigm

Journal of Diabetes Science and Technology ◽

10.1177/1932296819882719 ◽

2019 ◽

Vol 14 (6) ◽

pp. 1095-1103 ◽

Cited By ~ 1

Author(s):

John J. Wroblewski ◽

Christa McChancy ◽

Kassandra Pickel ◽

Hunter Buterbaugh ◽

Tyler Wieland ◽

...

Keyword(s):

Diabetic Retinopathy ◽

Correlation Coefficients ◽

Significant Negative Correlation ◽

Fundus Photography ◽

University Of Wisconsin ◽

Coefficients Of Variation ◽

Department Of Ophthalmology ◽

Patients With Diabetes ◽

Pearson Correlations ◽

Reading Center

Background: We evaluated the reproducibility of office-based flicker electroretinography (ERG) in patients with nonproliferative diabetic retinopathy (NPDR). Methods: An observational study was conducted in which ultra-widefield fluorescein angiography (UWF-FA) was performed on 20 patients with mild-to-moderate NPDR; images were graded by the Fundus Photography Reading Center (Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI, USA). Fixed- and multi-luminance flicker ERG was repeated four times (greater than or equal to seven days apart). Recording consistency was assessed using intra-class correlation coefficients (ICCs), coefficients of variation, and Pearson correlations. Results: 82.5% and 17.5% of eyes had mild and moderate NPDR using UWF-FA; 90% of the angiograms were given a high confidence grade. Fixed-luminance phase values were highly reproducible (ICC: 0.949; P < .001). There was a significant negative correlation between fixed-luminance phase and log-corrected ischemic index values (−0.426; P = .015). Conclusions: Office-based, fixed-luminance phase values are highly reproducible and negatively correlate with retinal ischemia in NPDR, suggesting that global retinal dysfunction may be reliably quantified early in patients with diabetes.

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Action Boundary Proximity Effects on Perceptual-Motor Judgments

Aerospace Medicine and Human Performance ◽

10.3357/amhp.5376.2019 ◽

2019 ◽

Vol 90 (12) ◽

pp. 1000-1008

Author(s):

Caleb D. Johnson ◽

Alice D. LaGoy ◽

Gert-Jan Pepping ◽

Shawn R. Eagle ◽

Anne Z. Beethe ◽

...

Keyword(s):

Intraclass Correlation ◽

Reaction Times ◽

Correlation Coefficients ◽

Proximity Effects ◽

Testing Time ◽

Good Reliability ◽

Intraclass Correlation Coefficients ◽

Coefficients Of Variation ◽

Time Required ◽

Action Coupling

INTRODUCTION: Designed as a more ecological measure of reaction times, the Perception-Action Coupling Task (PACT) has shown good reliability and within-subject stability. However, a lengthy testing period was required. Perceptual-motor judgments are known to be affected by proximity of the stimulus to the action boundary. The current study sought to determine the effects of action boundary proximity on PACT performance, and whether redundant levels of stimuli, eliciting similar responses, can be eliminated to shorten the PACT.METHODS: There were 9 men and 7 women who completed 4 testing sessions, consisting of 3 familiarization cycles and 6 testing cycles of the PACT. For the PACT, subjects made judgments on whether a series of balls presented on a tablet afford “posting” (can fit) through a series of apertures. There were 8 ratios of ball to aperture size (B-AR) presented, ranging from 0.2 to 1.8, with each ratio appearing 12 times (12 trials) per cycle. Reaction times and judgment accuracy were calculated, and averaged across all B-ARs. Ratios and individual trials within each B-AR were systematically eliminated. Variables were re-averaged, and intraclass correlation coefficients (ICC) and coefficients of variation (CVTE) were calculated in an iterative manner.RESULTS: With elimination of the 0.2 and 1.8 B-ARs, the PACT showed good reliability (ICC = 0.81–0.99) and consistent within-subject stability (CVTE = 2.2–14.7%). Reliability (ICC = 0.81–0.97) and stability (CVTE = 2.6–15.6%) were unaffected with elimination of up to 8 trials from each B-AR.DISCUSSION: The shortened PACT resulted in an almost 50% reduction in total familiarization/testing time required, significantly increasing usability.Johnson CD, LaGoy AD, Pepping G-J, Eagle SR, Beethe AZ, Bower JL, Alfano CA, Simpson RJ, Connaboy C. Action boundary proximity effects on perceptual-motor judgments. Aerosp Med Hum Perform. 2019; 90(12):1000–1008.

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The Yo-Yo Intermittent Endurance Level 2 Test: Reliability of Performance Scores, Physiological Responses and Overload Characteristics in Competitive Soccer, Basketball and Volleyball Players

Journal of Human Kinetics ◽

10.2478/hukin-2018-0091 ◽

2019 ◽

Vol 67 (1) ◽

pp. 223-233 ◽

Cited By ~ 1

Author(s):

Konstantinos Papanikolaou ◽

Athanasios Chatzinikolaou ◽

Theodoros Pontidis ◽

Alexandra Avloniti ◽

Chariklia K. Deli ◽

...

Keyword(s):

Correlation Coefficients ◽

Total Sample ◽

Test Reliability ◽

Maximum Speed ◽

Endurance Capacity ◽

Intra Class Correlation ◽

Coefficients Of Variation ◽

Volleyball Players ◽

Body Load ◽

Level 2

AbstractThe purpose of this study was to evaluate the reliability and reproducibility of the physiological and overload features of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2) in competitive male soccer (n = 20), basketball (n = 11), and volleyball players (n = 10). The participants completed Yo-Yo IE2 tests on three separate occasions with assessment of performance, heart rate, running speed, accelerations, decelerations and body load using GPS instrumentation. The intra-class correlation coefficient index, confidence intervals and coefficients of variation were calculated to assess the reliability of the test. Intra-class correlation coefficients for test-retest trials in the total sample ranged from large to nearly perfect (total distance: 0.896; mean speed: 0.535; maximum speed: 0.715; mean HR: 0.876; maximum HR: 0.866; body load: 0.865). The coefficients of variation for distance, mean speed, HR response, as well as acceleration and deceleration scores for test-retest trials ranged from 1.2 to 12.5% with no differences observed among particular sport disciplines. The CV for shuttles performed ranged from 4.4 to 5.5% in all sports. Similar results were obtained for the three different categories of players tested. These results suggest that the Yo-Yo IE2 test appears to be a reliable alternative for evaluating the ability to perform intermittent high-intensity running in different outdoor and indoor team sports. Players may need one or two familiarization tests to ensure valid assessment of intermittent endurance capacity. It appears that the Yo-Yo IE2 test incorporates accelerations and decelerations in a consistent and reproducible fashion.

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