Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Multi-Center Calibration of the Third BCR Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149S

1995 ◽  
Vol 74 (06) ◽  
pp. 1465-1467 ◽  
Author(s):  
A M H P van den Besselaar
Keyword(s):  
Reference Material ◽  
Collaborative Study ◽  
Sensitivity Index ◽  
Term Stability ◽  
Long Term Stability ◽  
Reference Preparation ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative study by eleven laboratories performed within the framework of the European Community Bureau of Reference (BCR), a third reference material for thromboplastin, rabbit, plain, has been calibrated against RBT/90, the current WHO international reference preparation for thromboplastin, rabbit, plain. This third reference material (coded CRM 149S) has a mean International Sensitivity Index (ISI)of 1.257 with a standard error of the mean of 0.013.The previous BCR reference material for thromboplastin, rabbit, plain (coded CRM 149R) and the reference material for thromboplastin, bovine, combined (coded OBT/79) were also included in the trial for assessment of the long-term stability of the ISI values. The relationship between ISI values determined in the present study was nearly identical to that of the historical values. These results offer reassurance with regard to the long-term stability of these reference materials.

A Reassessment of the Relationship between International Reference Preparations for Human and Rabbit Thromboplastins

2002 ◽  
Vol 88 (09) ◽  
pp. 459-461 ◽  
Author(s):  
A. Tripodi ◽  
M. H. P. A. van den Besselaar
Keyword(s):  
Sensitivity Index ◽  
International Reference ◽  
Calibration Study ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryTwo established international reference preparations (IRP) for thromboplastins, i.e. RBT/90 (rabbit, plain) and rTF/95 (recombinant human, plain) have been calibrated against each other in a 7-centre exercise performed in 2000. The purpose of the study was to compare the calibration results with those of the original calibration study performed in 1995. The international sensitivity index (ISI) for rTF/95 was calculated relative to the ISI for RBT/90. The mean ISI for rTF/95 was 0.961 (between-lab SD 0.028) which was 2% greater than the historical value determined in 1995. There is no indication that the two IRP have deteriorated, but further monitoring of the calibration relationship is recommended.

Effect of Concentration of Trisodium Citrate Anticoagulant on Calculation of the International Normalised Ratio and the International Sensitivity Index of Thromboplastin

1994 ◽  
Vol 72 (01) ◽  
pp. 084-088 ◽  
Author(s):  
E M Duncan ◽  
C R Casey ◽  
B M Duncan ◽  
J V Lloyd
Keyword(s):  
Reference Material ◽  
Oral Anticoagulants ◽  
Reference Method ◽  
Trisodium Citrate ◽  
Sensitivity Index ◽  
Blood Samples ◽  
Orthogonal Regression ◽  
Significant Difference ◽  
International Normalised Ratio ◽  
International Sensitivity Index

SummaryThe aim of this study was to determine whether the concentration of trisodium citrate used to anticoagulate blood has an effect on the INR of the sample and the ISI of the thromboplastin. Five thromboplastins including and Australian reference material were used to measure the prothrombin time of normal and patient samples collected into two concentrations of trisodium citrate - 109 mM and 129 mM. There was no effect of citrate concentration on the INRs determined with the reference material. However for the other four thromboplastins there was a significant difference between INRs for the two citrate groups. The prothrombin times of the samples collected into 129 mM were longer than those collected into 109 mM. This difference was only slight in normal plasma but more marked in patients receiving oral anticoagulants, causing the INRs for patient plasmas collected into 129 mM citrate to be higher then the corresponding samples collected into 109 mM citrate.From orthogonal regression of log prothrombin times by the reference method against each thromboplastin, we found that the ISI for each thromboplastin was approximately 10% lower when determined with samples collected into 129 mM citrate than with samples collected into 109 mM. These results suggest that the concentration of trisodium citrate used for collection of blood samples can affect the calculation of the INR and the calibration of the ISI of thromboplastin. This was found both for commercial thromboplastins prepared by tissue extraction and for a recombinant tissue factor.

Multi-Center Study of Thromboplastin Calibration Precision – Influence of Reagent Species, Composition, and International Sensitivity Index (ISI)

1993 ◽  
Vol 69 (01) ◽  
pp. 035-040 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Oral Anticoagulants ◽  
International Normalized Ratio ◽  
The Other ◽  
World Health ◽  
Rabbit Brain ◽  
Sensitivity Index ◽  
Bovine Plasma ◽  
Significant Difference ◽  
The Mean ◽  
International Sensitivity Index

SummaryFour thromboplastin reagents were tested by 18 laboratories in Europe, North-America, and Australasia, according to a detailed protocol. One thromboplastin was the International Reference Preparation for ox brain thromboplastin combined with adsorbed bovine plasma (coded OBT/79), and the second was a certified reference material for rabbit brain thromboplastin, plain (coded CRM 149R). The other two thromboplastin reagents were another rabbit plain brain thromboplastin (RP) with a lower ISI than CRM 149R and a rabbit brain thromboplastin combined with adsorbed bovine plasma (RC). Calibration of the latter two reagents was performed according to methods recommended by the World Health Organization (W. H. O.).The purpose of this study was to answer the following questions: 1) Is the calibration of the RC reagent more precise against the bovine/combined (OBT/79) than against the rabbit/plain reagent (CRM 149R)? 2) Is the precision of calibration influenced by the magnitude of the International Sensitivity Index (ISI)?The lowest inter-laboratory variation of ISI was observed in the calibration of the rabbit/plain reagent (RP) against the other rabbit/plain reagent (CRM 149R) (CV 1.6%). The highest interlaboratory variation was obtained in the calibration of rabbit/plain (RP) against bovine/combined (OBT/79) (CV 5.1%). In the calibration of the rabbit/combined (RC) reagent, there was no difference in precision between OBT/79 (CV 4.3%) and CRM 149R (CV 4.2%). Furthermore, there was no significant difference in the precision of the ISI of RC obtained with CRM 149R (ISI = 1.343) and the rabbit/plain (RP) reagent with ISI = 1.14. In conclusion, the calibration of RC could be performed with similar precision with either OBT/79 or CRM 149R, or RP.The mean ISI values calculated with OBT/79 and CRM 149R were practically identical, indicating that there is no bias in the ISI of these reference preparations and that these reference preparations have been stable since their original calibration studies in 1979 and 1987, respectively.International Normalized Ratio (INR) equivalents were calculated for a lyophilized control plasma derived from patients treated with oral anticoagulants. There were small but significant differences in the mean INR equivalents between the bovine and rabbit thromboplastins. There were no differences in the interlaboratory variation of the INR equivalents, when the four thromboplastins were compared.

scholarly journals Development of a Water Matrix Certified Reference Material for Volatile Organic Compounds Analysis in Water

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4370
Author(s):  
Liping Fang ◽  
Linyan Huang ◽  
Gang Yang ◽  
Yang Jiang ◽  
Haiping Liu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Reference Material ◽  
Organic Compounds ◽  
Certified Reference Material ◽  
Pure Water ◽  
Term Stability ◽  
Long Term Stability ◽  
Water Matrix ◽  
Volatile Organic

Water matrix certified reference material (MCRM) of volatile organic compounds (VOCs) is used to provide quality assurance and quality control (QA/QC) during the analysis of VOCs in water. In this research, a water MCRM of 28 VOCs was developed using a “reconstitution” approach by adding VOCs spiking, methanol solution into pure water immediately prior to analysis. The VOCs spiking solution was prepared gravimetrically by dividing 28 VOCs into seven groups, then based on ISO Guide 35, using gas chromatography-mass spectrometry (GC-MS) to investigate the homogeneity and long-term stability. The studies of homogeneity and long-term stability indicated that the batch of VOCs spiking solution was homogeneous and stable at room temperature for at least 15 months. Moreover, the water MCRM of 28 VOCs was certified by a network of nine competent laboratories, and the certified values and expanded uncertainties of 28 VOCs ranged from 6.2 to 17 μg/L and 0.5 to 5.3 μg/L, respectively.

The analysis of the results of a rotation experiment on the use of straw and fertilizers

1953 ◽  
Vol 43 (1) ◽  
pp. 77-88 ◽  
Author(s):  
H. D. Patterson
Keyword(s):  
Present Experiment ◽  
Treatment Effects ◽  
Standard Errors ◽  
Methods Of Analysis ◽  
Seasonal Factors ◽  
Long Term Experiments ◽  
The Mean ◽  
Linear Regressions

An experiment, designed to test different ways of using straw with fertilizers, and involving a three course rotation of crops, was carried out at Rothamsted between 1933 and 1951. The methods of analysis developed for this experiment are described in the present paper and demonstrated using yields of potatoes.Treatment effects of interest are given by the mean yields over all years and the linear regressions of yield on time. These estimates are straightforward but the evaluation of their errors is complicated by the existence of correlations due to the recurrence of treatments on the same plots. Further complications are introduced when, as frequently happens in long-term experiments, treatment effects show real variation from year to year. A method is given for estimating standard errors which include a contribution from this variation.The various relationships between yields and the uncontrolled seasonal factors can also be examined; in the present experiment there is some indication that the effects of treatments on yields of potatoes are influenced by the dates of planting.In other circumstances the analysis requires modifications, some of which are briefly considered.

scholarly journals Standard Error of the Mean and Minimal Detectable Change of Gait Speed in Older Adults Using Japanese Long-Term Care Insurance System

2021 ◽  
Vol 7 ◽  
pp. 233372142110489
Author(s):  
Yui Takada ◽  
Shigeharu Tanaka
Keyword(s):  
Older Adults ◽  
Standard Error ◽  
Gait Speed ◽  
Long Term Care ◽  
Minimal Detectable Change ◽  
Detectable Change ◽  
Term Care ◽  
Long Term Care Insurance ◽  
The Mean

Evaluation of motor function, such as gait ability, can accurately predict the subsequent occurrence of disability in older adults. There are no reports of standard error of the mean (SEM) or minimal detectable change (MDC) with respect to gait in Japanese long-term care insurance-certified individuals. The purpose of this study was to investigate the values of preferred gait, fast gait, and the timed up and go (TUG) test. This study included 46 participants using the Japanese long-term care insurance system. (age 86.5 ± 6.6 years, 12 men, 34 women). The duration of three gait were measured twice using a stopwatch. The SEM was 0.07 for preferred gait, 0.09 for fast gait and 2.59 for TUG. The MDC was 0.19 for preferred gait, 0.26 for fast gait, and 7.17 for TUG. The SEM and MDC values of preferred gait, fast gait, and TUG in this study corroborated with those of previous studies, whereas others were different. Considering that gait speed differs with the country, it may be difficult to compare it among different population groups. We obtained the results of gait speed of Japanese long-term care insurance-certified individuals, which is a new finding

Laying date of marsh tits Parus palustris in relation to climate change

Biologia ◽  
2006 ◽  
Vol 61 (5) ◽  
Author(s):  
Zdravko Dolenec
Keyword(s):  
Climate Change ◽  
Life History Traits ◽  
Laying Date ◽  
Bird Breeding ◽  
Spring Temperatures ◽  
The Mean ◽  
The Relationship ◽  
Marsh Tit ◽  
Term Data

AbstractIncreasing evidence suggests that climate change affects bird breeding phenology and other life-history traits of wildlife. This study is based on the mean spring temperatures (February, March, April) and laying dates of first eggs of the marsh tit Parus palustris. We collected data from 1984 to 2004 for the Mokrice area in NW Croatia. Correlation between laying date and mean spring temperatures was significant. The relationship between mean laying date (y) and air temperature (x) can be expressed as y = 44.69 − 2.08x. Results indicate that spring temperatures are a good predictor of timing of laying eggs. Such long-term data could than be used in order to assess the effects on biological systems if human activities influence climate.

Class II treatment in early mixed dentition with the eruption guidance appliance: effects and long-term stability

2019 ◽  
Vol 42 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Katri Keski-Nisula ◽  
Leo Keski-Nisula ◽  
Juha Varrela
Keyword(s):  
Treatment Group ◽  
Class Ii ◽  
Post Treatment ◽  
Mixed Dentition ◽  
Term Stability ◽  
Long Term Stability ◽  
Class Ii Treatment ◽  
Significant Correction ◽  
The Mean

Summary Objectives Our aim was to analyse dentoskeletal effects and long-term stability of Class II treatment carried out with an eruption guidance appliance (EGA) in early mixed dentition. Materials and methods Sixty-five Class II patients (38 females and 27 males), treated with an EGA in early mixed dentition, were compared with 58 children (26 females and 32 males) with untreated Class II malocclusion. The mean age in the treatment group at the start (T1) and end of treatment (T2) was 5.4 years (±0.4) and 8.5 years (±0.9), respectively, and at the final examination in the early permanent dentition (T3) 16.7 years (±0.4). In the control group, the mean age at T1 and T2 were 5.1 years (±0.5) and 8.4 years (±0.5), respectively. The independent and dependent sample t-tests, Chi-square test, and Fisher’s test were used in the statistical evaluation. Results In the treatment group, the frequency of Class II decreased from 100 to 14% during the treatment (T1–T2) and a significant correction took place in all occlusal variables. At T2, the treatment and control groups showed statistically significant differences (P < 0.05) in all occlusal variables. In the treated children, mandibular length increased 5 mm more (P < 0.001) from T1 to T2 compared to the control children, and the ANB angle became significantly smaller (P = 0.006). During the post-treatment period (T2–T3), the frequency of Class II in the treatment group decreased from 14 to 2% (P < 0.05), overbite increased from 2.2 to 3.1 mm (P < 0.05), and lower crowding increased from 2to 14% (P < 0.05). Post-treatment changes in overjet and upper crowding were not statistically significant. At T3, the mean values of the SNA, SNB, and ANB angles were 83.0° (SD 3.9°), 81.3° (SD 3.8°), and 2.4° (SD 1.5°), respectively. Conclusions A clinically significant correction of the molar relationship, overjet, overbite, incisor alignment, and growth enhancement of the mandible were observed after treatment in early mixed dentition. The treatment results remained largely stable in the early permanent dentition. However, an increase was observed in overbite and lower crowding. None of the children treated in early mixed dentition needed a second treatment phase.

scholarly journals Analyses of Monthly Discharges in Slovakia Using Hydrological Exploratory Methods

Proceedings ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 18
Author(s):  
Mária Ďurigová ◽  
Dominika Ballová ◽  
Kamila Hlavčová
Keyword(s):  
Change Points ◽  
Hydrological Data ◽  
Pettitt Test ◽  
The Mean ◽  
Monthly Discharge ◽  
Meteorological Elements ◽  
The Relationship ◽  
Annual Discharge ◽  
Hydrological Regimes

Detailed analyses of hydrological data are necessary in order to prove changes in their character. This article focuses on an analysis of the average monthly discharges of 14 stage-discharge gauging stations in Slovakia. The measured period is from 1931 to 2016. The approaches used are hydrological exploration methods, which were created by hydrologists to describe the behavior of hydrological time series. The methods are used to identify a change-point using an analysis of any residuals, the Pettitt test, and an analysis of the relationship between the mean annual discharge deviations from the long-term annual discharge and the deviations of the average monthly discharge from the long-term average monthly discharge. A considerable number of change-points were identified in the 1970s and 1980s. The results of the analyses show changes in the hydrological regimes, but to confirm the accuracy of the outcomes, it is also necessary to examine other hydrological and meteorological elements such as, e.g., precipitation and the air temperature.

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