[Reproducibility of details in Brazilian laboratories duplicating materials submitted to repeated heating-gelation cycles].
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Dental Impression Materials↗
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Results for “Repeatability and Reproducibility”
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Atomic absorption spectrophotometric determination of mercury in mercury-containing drugs: collaborative study.
An atomic absorption spectrophotometric (AAS) method applicable to a wide variety of mercury-containing drugs has been developed and subjected to a collaborative study. Samples were digested with a water-HCl-HNO3 (4 + 3 + 1) mixture, and the mercury was determined in solution by AAS. High levels of mercury were measured with a conventional air-acetylene flame, whereas low levels were measured by the flameless technique. Each of 7 collaborators received duplicate synthetic samples of a tincture, an ophthalmic solution, and an antiseptic solution, and duplicate commercial samples of an ointment and an injectable. The overall mean value found by collaborators for mercury in these samples was 100.13%. The corresponding overall repeatability SD (CV, %) and reproducibility SD (CV, %) values were 2.18 (2.18) and 3.38 (3.38), respectively. The proposed AAS method has been adopted official first action.
Mercury↗
Krimpsiekte and acute cardiac glycoside poisoning in sheep caused by bufadienolides from the plant Kalanchoe lanceolata Forsk.
Three toxic bufadienolides , one characterized as hellibrigenin 3-acetate, have been isolated from Kalanchoe lanceolata Forsk. Typical signs of cardiac glycoside poisoning, involving the gastro-intestinal, neuromuscular and cardiovascular systems, could be induced by drenching the milled plant to sheep. Such signs could also be induced by dosing the bufadienolides to sheep or by injecting them into both guinea-pigs (subcutaneously) and sheep (intravenously). The specific paretic syndrome, krimpsiekte , on the other hand, was reproduced only by the repeated intravenous administration of smaller doses of the 2 unknown bufadienolides to sheep. Histopathological examination revealed a mild to severe multifocal cardiomyopathy in sheep receiving plant material or bufadienolides .
Acute Disease↗
Evaluation of a crude soluble antigen from in-vitro culture of Plasmodium falciparum for ELISA.
The present study was to evaluate the soluble antigen prepared from the in-vitro cultured P. falciparum (FCR3) as an alternative source of antigen to those obtained from in-vivo models for enzyme linked immunosorbent assay (ELISA) in serology of malaria. Results obtained on known positive and negative reference sera revealed good correlation between the ELISA and the indirect fluorescent antibody (IFA) technique (rs = 0.797; p less than 0.001). However such close correlation was not observed on six local sera from patients whose peripheral blood smear showed ring stage of P. falciparum (rs = 0.43; p greater than 0.05), though all the six sera were positive by the IFA and ELISA tests. Test was repeated to establish its reproducibility. The results indicate that antigen prepared from in vitro culture and stored in liquid nitrogen was found sensitive in ELISA for serology of malaria.
Antibodies↗
[Use of reference plasmas for estimating the accuracy of radioimmunological titration measurements].
This article presents a method for estimating the variability of measurements in radio-immunoassays. Repeated assays are carried out on the same plasma used as a reference. The variances of repeatability (or intraassay) and reproducibility are calculated from the values obtained from the reference. These variances are used to calculate the agreement between two or more values obtained from unknown plasma. Analysis of the values of the plasma reference completes information obtained from standard curves.
Analysis of Variance↗
Detection of invasiveness of mammalian cells by Escherichia coli: collaborative study.
In a collaborative study of 2 standard procedures (Procedure I, presented in J. Assoc. Off. Anal. Chem. 60, 546-562 (1977) and Procedure II in the Bacteriological Analytical Manual, 1978), 7 laboratories evaluated the invasive potential of Escherichia coli. Monolayers of HeLa cultures were infected with E. coli (infectivity ratio 100 bacteria/mammalian cell) suspended in 2 menstrua: heat-inactivated fetal bovine serum (Procedure I) and 0.2% bovine albumin Fraction V dissolved in Earle's buffered salts (Procedure II). After uptake of the bacteria, intracellular growth, and differential staining, the percentages of HeLa cells containing a minimum of 5 bacteria were determined microscopically. All laboratories correctly identified invasiveness of E. coli by Procedure I; 5 of 6 laboratories recognized invasiveness by Procedure II. Although Procedure I was more reproducible than Procedure II, repeatability did not differ significantly. Procedure I was adopted official first action for presumptive recognition of invasiveness in E. coli.
Bacteriological Techniques↗
[Usual values of serum vitamin A using a modified fluorimetric method].
We report a fluorimetric technique for the determination of serum vitamin A. The critical study of this micromethod included trials of repeatability, inter-series reproducibility and an evaluation of its accuracy. It was compared with a method using high performance liquid chromatography followed by detection with UV spectrophotometry. Normal values were established for adults. The variations according to age were determined for children between the ages of 10 months and 15 years.
Adolescent↗
Reproducibility of the laser flare meter and laser cell counter in assessing anterior chamber inflammation following cataract surgery.
BACKGROUND AND OBJECTIVES: To determine the interobserver and intraobserver reproducibility of the laser flare meter and laser cell counter in assessing anterior chamber inflammation following cataract surgery. PATIENTS AND METHODS: Thirty-nine eyes with varied degrees of inflammation and 9 normal eyes were included in the study. Anterior chamber flare and cells were evaluated with the slit lamp and graded on a scale of 0 to 4+. The flare and cells were then measured three times each using the flare meter and cell counter by two different, experienced observers. The intraobserver reproducibilities were computed to evaluate repeatability of the instruments operated by the same observer. The first measurement taken by each observer was used to assess reproducibility between the two observers. RESULTS: The intraobserver reproducibility for overall flare was 0.995 for both observers. The intraobserver reproducibility for overall cells was 0.996 for observer 1 and 0.991 for observer 2. The overall interobserver reproducibility was 0.994 for flare and 0.988 for cells. The correlation between measurements and slit-lamp ratings was 0.78 for flare and 0.56 for cells. CONCLUSIONS: The intraobserver and interobserver reproducibilities were excellent, with good correlation to slit-lamp measurements. Reproducible results can be obtained using the laser flare meter and the laser cell counter. It is not known whether these results are applicable to other inflammatory processes with higher grades of flare and cells and with different protein and cell types.
Anterior Chamber↗
[Measure of splanchnic blood flow by marker dilution: comparison of 4 methods of para-aminohippuric acid determination].
The objective of this study was to determine the influence of the analytical method of para aminohippuric acid (PAH) on splanchnic blood flows, as measured by a dye dilution method in ovines. Four different analytical methods of PAH were compared. They differed in the pretreatment of the samples and in the presence or absence of a deacetylation step to account for the partial acetylation of PAH in the liver (13%). The optimum conditions of deacetylation were defined as 60 min of incubation at 90 degrees C in presence of HCl (5N). The four analytical methods were checked to be linear (from 0 to 35 mg/L), repeatable (CV = 0.70%) and reproducible (CV = 2.1%). It appeared necessary to prepare the standards in the same matrix as that of the samples. The choice of the analytical method was responsible for differences in PAH concentrations and in the absolute values for portal and hepatic blood flows, which could reach 21%. The presence of a deacetylation step with HCl significantly reduced the contribution of the hepatic artery to the total hepatic blood flow (from 24 to 10%). Consequently, this study showed that the nature of the analytical method chosen can highly influence the measurements of splanchnic nutrient fluxes. The recommended analytical method is the one which includes a deacetylation step.
Acetylation↗
The reproducibility of color Doppler duplex sonography in the measurement of renal arterial blood velocity.
In this study, the reproducibility of color Doppler duplex sonography for repeated measurements of renal blood flow was evaluated in 14 healthy subjects. We examined the reproducibility for different examiners and different time intervals between the examinations. Doppler frequency sonograms were analyzed with several parameters, and statistical evaluation was performed by calculating both the correlation coefficient (r) and coefficient of variation (CV). Peak systolic velocity (S), early diastolic velocity (D1) and mean velocity (MV) showed good reproducibility (r = 0.902-0.992, CV = 2.15-8.16%). On the other hand, end-diastolic velocity (D2), acceleration time (AT) and acceleration index (AI) showed poor reproducibility. We conclude that the reproducibility of this method is acceptable for repeated measurements of renal blood velocity, using suitable parameters S, D1 and MV.
Adult↗
Panoramic mandibular index as a radiomorphometric tool: an assessment of precision.
OBJECTIVES: To evaluate the intra-observer repeatability and inter-observer reproducibility of the measurements used in deriving the Panoramic Mandibular Index (PMI). METHODS: Two observers measured 21 dental panoramic radiographs independently of each other, both repeating the measurements after a period of 1 week. The measurements were then evaluated using a number of statistical methods. RESULTS: All sets of compared measurements, both within and between observers, demonstrated significant positive correlations, with no significant difference between measurements Precision, however, was poor and variable. CONCLUSION: The main difficulties in obtaining consistency in repeated measurements were related to individual morphology and radiodensity. In order to improve the validity of the PMI as a measure of local bone loss, repeatability of the measurements should be improved. Suggestions as to how this, might be achieved are discussed.
Absorptiometry, Photon↗
In vitro evaluation of porcine lymphocyte response to phytohaemagglutinin using a modified "whole blood" technique.
The purpose of these investigations was to develop a modified whole blood technique for measuring quantitatively the responsiveness of pig peripheral blood lymphocytes to phytohemagglutinin (PHA) in vitro. Washed blood cells from a fixed volume of blood were suspended in culture medium supplemented with foetal calf serum and stimulated with a pure mitogenic PHA preparation. The stimulation was measured by the incorporation of 3H-thymidine. Data are presented to show the effect of different variables on the culture system. The transformation response was measured at different levels of PHA and the reproducibility of the different responses from repeated investigations was used to evaluate the usefulness of the test. The best reproducibilities of the stimulation response were found at the high PHA concentrations. Also the calculated PHA concentration giving maximum stimulation response had a relatively high reproducibility and indicates that this value is a convenient and reliable alternative measure of the functional capacity of the lymphocytes.
Animals↗
Generic versus disease-specific instruments in quality-of-life assessment of chronic obstructive pulmonary disease.
OBJECTIVES: Chronic respiratory diseases may alter a patient's social life and well-being. Measures of health-related quality of life have been proven to bring complementary information to functional assessments. The aim of the study was to describe the questionnaires that are most frequently used to measure this subjective construct in patients with chronic obstructive pulmonary disease (COPD) and to compare the responses obtained via administering one generic (SF-36) and one disease-specific questionnaire (St. George's Respiratory Questionnaire; SGRQ) to patients with COPD. METHODS: One group of patients (46 individuals) was used to evaluate the questionnaire's performance in repeated administrations under unchanged conditions (reproducibility) and to study the correlations of corresponding domains of respective questionnaires. Responsiveness of both questionnaires was tested on another group of 129 patients measured before and after the therapeutic stay at the spa. Methods of correlational analysis (Spearman, intraclass, and canonical correlation coefficients) as well as the Wilcoxon rank test were used for statistical analysis. RESULTS: Both questionnaires seem to be comprehensive outcome measures for patients with COPD, but some particular areas may not be covered with the same intensity (e.g. emotional problems). Reproducibility of both questionnaires was good and only small non-significant shifts were seen, particularly in physical and social functioning domains. In repeated measurement, the SGRQ seemed to be slightly more responsive to change than the SF-36. CONCLUSIONS: The idea of using generic and disease-specific questionnaires together probably represents the best approach to this topic. It may improve our knowledge and explain better the relationship between disease-specific changes in patient status and both disease-specific treatment and general functional status.
Czech Republic↗
Reproducibility of positive test results in the BDProbeTec ET system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae.
Nucleic acid amplification tests such as the BDProbeTec ET (BDPT) system are more prone to reproducibility problems than are antigen detection tests and culture. A repeat testing algorithm for all samples with method other than acceleration (MOTA) scores greater than or equal to the cutoff value (2000) was developed for the BDPT system and applied in a clinical laboratory setting. All positive samples were retested, and if the result of the second test was below the cutoff value, a third test was performed to resolve the discrepancy. Overall, 11 (5.3%) of 207 samples initially positive for Chlamydia trachomatis and 11 (10.7%) of 103 samples initially positive for Neisseria gonorrhoeae were not confirmed by repeat testing of the original sample. Poor reproducibility was associated with low-positive MOTA scores (2000 to 9999) for both analytes. Only 21 (80.8%) of 26 low-positive samples in the C. trachomatis test and 4 (33.3%) of 12 low-positive samples in the N. gonorrhoeae test retested as positive. The reproducibility of both tests with samples with initial MOTA scores of >or=10000 increased to 96.7%. The data suggest that retesting of low-positive samples is warranted and could reduce the number of potentially false-positive test results.
Algorithms↗
[Comparison and reproducibility of 4 methods of indirect blood pressure measurement in moderate hypertension].
UNLABELLED: The measurements and the reproducibility of ambulatory, home, clinic and repeated non ambulatory automatic blood pressure (BP) were compared in 16 patients (45 +/- 11 yrs) with mild untreated hypertension (BP: 164 +/- 12/101 +/- 6 mmHg at the selection visit); 26 +/- 19 days after this visit, each patient had two sets of BP measurements in 4 different ways taken 2 weeks apart under similar study conditions: daily ambulatory recordings (ABP), home self-measurement readings (over 5 days) (HBP), 2-minute repeated automatic BP measurements during the 20 minutes preceding the physician examination (RABP) and clinic BP (CBP) with a standard sphygmomanometer mercury column. The reproducibility was assessed by standard deviation of the differences (SDD). Decisions to treat the patients were made according to the results obtained by CBP (BP > 140/90 mmHg during the selection visit and the 2 study visits), by the first ABP (mean BP > 139/87 mmHg) and by the first week of HBP (mean BP > 127/83 mmHg) were compared; the outcome of these three procedures was then compared. RESULTS: [table: see text] CONCLUSION: Repeated automatic and clinic BP were higher than ambulatory and home BP. Reproducibility of ambulatory and home BP were comparable and better than clinic or repeated automatic BP. The percentage of decision to treat according to the results of clinic, home and ambulatory BP was comparable but they were not the same patients who were treated with the 3 methods.
Adult↗
Interpretation of an abnormal oral glucose tolerance test encountered during multiphasic laboratory screening.
We have studied 162 healthy male flyers who had repeat glucose tolerance tests at intervals of 6 months to 2 years. On the premise that an abnormal oral glucose tolerance test (OGTT) was not reproducible because standard criteria were not strict enough, we evaluated 11 different criteria for diagnosing an abnormal OGTT. The number of abnormal tests varied according to the criteria but, no matter how the criteria were varied, the best reproducibility of any abnormal test on repeat testing was 50%. Factors affecting the reproducibility of an abnormal test are discussed. We conclude that a single, standard 2-h oral glucose tolerance test should be considered only as a screening test for diabetes mellitus, and that a final diagnosis of chemical diabetes mellitus should be made only if the carbohydrate in-tolerance consistently worsens or if insulin curves show hypofunction of the Islets of Langerhans. Our recommendations for followup studies of a patient with an initial abnormal OGTT are outlined. This study illustrates the importance of basic definitions of diagnostic criteria for diseases which have a long-term effect on the health of the flying population.
Adolescent↗
Validation protocol of analytical hemostasis systems: measurement of anti-Xa activity of low-molecular-weight heparins.
A standard validation protocol adapted to the chromogenic assay of anti-Xa activity of low-molecular-weight heparins was used in a multicenter study to assess its suitability for comparing and evaluating analytical hemostasis systems. The protocol included: familiarization with the system (repeatability); assessment of limits of linearity, detection limits, and cross-contamination; and validation (reproducibility and accuracy of measurements of treated patients' plasmas). We calibrated the systems with the same range of lyophilized plasmas daily and evaluated repeatability and reproducibility by using a single batch of lyophilized plasmas at three anti-Xa activities. The two automated systems tested [SB 300 (Gilford) and ACL (IL)] and the two semiautomated systems [ST 888 (D. Stago) and Chromotimer (Behring)] gave similar mean values. Dispersion of results was lower with the automated systems than with the semiautomated ones, especially at low anti-Xa activities, a tendency that also was observed for reproducibility. Because each analytical system gave linear results for activities as great as 1000 IU/L, suitable sample dilution is advisable for higher anti-Xa activities. Accuracy was greater in the automated systems. We conclude that this protocol is feasible and is applicable to validation of other analytical hemostasis instruments, in particular the latest generation of fully automated instruments.
Autoanalysis↗
The development and validation of an occlusal site-specific plaque index to evaluate the effects of cleaning by tooth brushes and chewing gum.
These studies sought to develop and validate an occlusal site-specific plaque index to be used to measure plaque removal by brushing or chewing gum. The index divides the occlusal surfaces into imaginary zones from which scores are apportioned on a 0-4 basis dependent on the perceived % plaque coverage of each zone. Examiner calibration was conducted over 2 studies assessing inter-examiner reproducibility and intra-examiner repeatibility, respectively. Study 1 involved 2 examiners who recorded scores from the same 3 groups of subjects who had suspended tooth cleaning for 4 days. Analyses for inter-examiner reproducibility showed no significant mean differences between examiners or no significant differences between variances of the 2 examiners scores. Study 2 involved the same 2 examiners individually scoring 3 groups of subjects 2 x (approximately 60 min apart) for occlusal plaque. Analysis for intra-examiner repeatability showed no significant mean differences between the 2 scorings of each examiner. Furthermore, there were no significant differences between the variances of each examiner's scores except for 1 examiner in the repeatability exercise for the 1st group of subjects. Study 3 involved groups of subjects at 2 separate clinical sites (Bristol, England and Berne, Switzerland) being scored for occlusal plaque before and after toothbrushing with water or after no toothbrushing. Data from individual examiners and examiners combined revealed a significant reduction in occlusal plaque with brushing compared to no brushing. Study 4 was the same as study 3 but occlusal plaque was scored before and after chewing gum or not chewing gum. The Bristol examiner recorded a significant reduction in plaque by chewing gum compared to not chewing gum but the Berne examiner did not. The latter may have resulted from a considerable disparity in the number of evaluable occlusal surfaces between the two study sites. The index could be employed as part of the overall assessment or oral hygiene or used in clinical trials to study mechanical and chemical plaque control agents.
Adult↗