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PubMed1988

Reproducibility of ambulatory oesophageal pH monitoring.

To evaluate the reproducibility of ambulatory 24 hour intraoesophageal pH monitoring, 20 patients were randomly selected to undergo two consecutive investigations. Fifteen patients were classified as either abnormal, or normal on both test days. The amount of acid reflux, expressed as percentage of time with oesophageal pH below 4.0 during the two 24 hour periods, showed 77% concordance. The upright and recumbent periods of measurement showed different degrees of concordance: 83% and 62%, respectively. The reproducibility during time periods of different length was found to increase with increasing length of day time pH recording. A 16 hour period during evening and night had a reproducibility of only 58%, however. It is concluded that there is fairly good reproducibility when measuring gastro-oesophageal reflux over 24 hours, but that the reproducibility is poorer at night, during the postprandial period and when daytime monitoring is shorter than 10 hours.

Adult↗

PubMed1980

Reproducibility of pulmonary function tests under laboratory and field conditions.

The reproducibility of pulmonary function tests in the laboratory and in a mobile field survey vehicle has been studied. Groups of laboratory workers were studied at base and a random sample of 38 coalminers was examined in the mobile laboratory. The intra-subject variability of some newer tests of lung function, including closing volume and maximum flow at low lung volumes, has been compared with that of well-established tests, such as lung volumes and forced expiratory volume from two measurements made more than one day apart. Most measurements were slightly less reproducible in the study of coalminers than in the laboratory personnel. Conventional tests, such as forced expiratory volume in one second, lung volumes, single breath CO transfer factor, and exercise ventilation were very reproducible, the coefficients of variation (cov) being generally between 5% and 10%. The closing volume test, maximum expiratory flow at low lung volumes, and the single breath N2 index were less reproducible: cov between 15% and 39% in the miners. The forced expired time and volume of isoflow, measured only on laboratory workers, however, exhibited greater reproducibility than previously reported (cov = 10% and 15% respectively). It is suggested that, when assessing the repeatability of lung function tests, account should be taken of the circumstances in which the intra-subject variability was measured.

Adolescent↗

PubMed2006

Validity and reproducibility of different combinations of methods for occlusal caries detection: an in vitro comparison.

This study assessed the validity and reproducibility of different combinations of occlusal caries detection methods: visual examination (VE), laser fluorescence (LF) and radiographic examination (RE). Intra- and interexaminer reproducibilities were also assessed. Forty-seven extracted human molars were used and 121 sites, either suspected or not to be carious, were chosen. Occlusal surfaces were examined by 8 volunteers, assigned to three groups according to their level of knowledge and clinical experience on dental practice: group I, undergraduate students; group II, postgraduate students; group III, professors. Three combinations of methods were tested: A: VE+LF, B: VE+RE, C: VE+LF+RE. The examiners scored the sites using ranking scales and chose a final score based on their clinical experience. The gold standard was determined by histological examination of the sites. In general, LF and RE yielded poorer results than the combinations of methods. For combination A, group III showed the highest sensitivity, while group II showed the highest specificity. For combination B, group II showed moderate sensitivity whereas groups I and III exhibited low sensitivities; all groups of examiners reached substantial specificity. For combination C, all groups exhibited moderate sensitivity and substantial specificity. Interexaminer reproducibility ranged from fair to moderate for combinations A and C, while for combination B kappa values indicated moderate interexaminer reproducibility. It may be concluded that individual exams presented inferior performance than the conjunction of them. Combination C (VE+LF+RE) resulted in the best accuracy for all groups. The knowledge background of the examiners influenced their ability to detect caries lesions and affected interexaminer reproducibility.

Dental Caries↗

PubMed1983

Short-term reproducibility of ergometric parameters in functional stress test after recent myocardial infarction.

In order to assess the short-term reproducibility of the most important ergometric parameters, 108 males (mean age 50.3 +/- 7.8 years) underwent a functional stress test (FST) on average 35 days after myocardial infarction. The exercise test was repeated 3 days later in the same conditions. Patients were fasting and in pharmacological washout. The following parameters were analyzed: total work performed (TWP), VO2, heart rate (HR), systolic blood pressure (SBP), arrhythmias and S-T segment depression and elevation. TWP and VO2 values did not show any significant difference during the two tests under the various workloads. HR and SBP responses proved to be well reproducible in patients with HR and SBP not exceeding the mean values obtained from 222 normal subjects who underwent the same exercise test by more than +/- 1 SD; reproducibility was significantly lower in the other patients, particularly in patients with HR and SBP exceeding normal values by more than +/- 1 SD. Therefore, in this case, further FST are necessary to obtain more reliable parameters to decide on individual pharmacological and exercise prescriptions. Arrhythmias were reproducible up to 67% (p less than 0.01) regardless of Lown's class and the presence of S-T segment depression or elevation. S-T segment depression or elevation was reproducible up to 100%.

Adult↗

PubMed2001

Safety and reproducibility of sputum induction in asthmatic subjects in a multicenter study.

The safety of sputum induction and the reproducibility of measurements in induced sputum in multicenter studies is unknown. We examined the safety of sputum induction in a two-visit, six-center study in 79 subjects with moderate to severe asthma (mean +/- SD FEV(1) 71 +/- 12% predicted, 67% taking inhaled corticosteroids). In addition, we compared the reproducibility of markers of inflammation in induced sputum with the reproducibility of the FEV(1) and the methacholine PC(20). The FEV(1) decreased > or = 20% from the postbronchodilator baseline in 14% of all subjects and in 25% of subjects whose initial prebronchodilator baseline was 40 to 60% of predicted. All subjects responded promptly to additional albuterol treatment, and no subject developed refractory bronchoconstriction requiring treatment other than reversal of bronchospasm in the study laboratory. The reproducibility of measurements of the eosinophil percentage, eosinophil cationic protein, tryptase, and methacholine PC(20) were similar (concordance correlation coefficients of 0.74, 0.81, 0.79, and 0.74, respectively), without any significant among-center effect. We conclude that sputum induction can be performed safely in subjects with moderate to severe asthma in multicenter clinical trials when carried out under carefully monitored conditions. Importantly, we demonstrate that measurement of markers of inflammation in induced sputum is as reproducible as methacholine PC(20) and should prove useful in the assessment of airway inflammation in multicenter clinical trials.

Aged↗

PubMed1977

Epidemiological evaluation of funduscopic findings in cerebrovascular diseases. III. Observer variability and reproducibility for funduscopic findings.

In order to evaluate observer variability and reproducibility for the funduscopic findings, the color slides of one hundred cases in Akabane and Asahi town in Japan were investigated and the following were revealed: 1. Observer variability for Keith-Wagener's classification was the least in the grade 3 and the most in grade 0. The variability of diagnosis between observers was the least for retinal bleeding and the most for anteriolar reflex and remarkable for lateral displacement and arteriolar narrowing. In general, the observe variability was one grade at most. 2. Reproducibility for Scheie's hypertensive classification was 73 per cent and that for Scheie's arteriosclerotic and Keith-Wagner's classifications was 66 per cent. Fairly good reproducibility was observed in retinal bleeding and poor reproducibility in arteriolar reflex and vertical and lateral displacements, In general, the intra-observer variability for the funduscopic findings was one grade at most. 3. Observer variability and reproducibility for the funduscopic findings would be improved by establishment of the detailed diagnostic criteria of various funduscopic findings, taking color pictures in focus and systematic training for the fresh doctors or technicians without enough experience. 4. The cases with definite narrowing of arteriole revealed smaller A/V ratio than 0.70.

Adult↗

PubMed1983

Cardiac output by thermodilution technique. Effect of injectate's volume and temperature on accuracy and reproducibility in the critically Ill patient.

We compared determinations of cardiac output using various combinations of injectate volumes and temperatures to results obtained with 10 ml of iced (0 degrees C) injectate (standard technique) in 33 critically ill patients. The use of a 10-ml injectate at room temperature resulted in comparable reproducibility (12.7 vs 10.8 percent; not significant) and a small and nonsignificant error (-0.013 +/- 0.543 L/min). Five milliliters at room temperature resulted in markedly decreased reproducibility (17.9 vs 8.9 percent; p less than 0.05); however, the error associated with the technique was still not significant (0.136 +/- 0.829 L/min). When a 5-ml injectate at 0 degrees C was used, a reproducibility comparable to that of 10 ml at 0 degrees C was obtained (12.3 vs 7.5 percent; not significant). The results underestimated values obtained with 10 ml at 0 degrees C (-0.360 +/- 0.857 L/minute); however, the difference did not reach statistical significance. The use of 3 ml at 0 degrees C was associated with a substantial increase in variability, with a coefficient of variation of 32.0 percent (10.4 percent for 10 ml of iced injectate; p less than 0.01); however, the differences between the average value of cardiac output obtained with this technique and the standard technique were only minimal (error, -0.063 +/- 0.455; not significant). We reached the following conclusions: (1) the use of 10 ml at room temperature and 5 ml at 0 degrees C as the indicator for thermodilution determinations of cardiac output results in small and insignificant differences in reproducibility and accuracy from the standard technique; (2) five milliliters at room temperature and 3 ml at 0 degrees C are associated with markedly decreased reproducibility; however, the error in values for cardiac output obtained with these techniques is not statistically significant; and (3) the ability to use injectate at room temperature and in small volume should substantially simplify the technique, lowering its cost, and should prevent volume overloading.

Adult↗

PubMed1984

The reproducibility of hemodynamic, electrocardiographic, and gas exchange data during treadmill exercise in patients with stable angina pectoris.

Fourteen male patients with exercise test-induced angina and ST-segment depression underwent treadmill testing on three consecutive days to evaluate the reproducibility of certain treadmill variables. Computerized ST-segment analysis and expired gas analysis, including anaerobic threshold, were evaluated for reproducibility using an intra-class correlation coefficient analysis. Measured oxygen uptake at peak exercise displayed better reproducibility than total treadmill time, the onset of angina, and the gas exchange anaerobic threshold (ATGE). The double product, heart rate, and ST-segment displacement in lead X were found to be reproducible at peak exercise, the onset of angina, and the ATGE. The incorporation of gas exchange analysis can provide accurate physiologic determinants of exercise capacity in patients with angina pectoris. In addition, noninvasive estimates of myocardial oxygen demand and ischemia can be reproducibly determined. These findings have important implications for the design of studies evaluating the effects of an intervention on angina pectoris.

Adult↗

PubMed1989

Reproducibility of ethanol elimination rates in long-sleep and short-sleep mice.

Ethanol metabolism was measured in long-sleep (LS) and short-sleep (SS) mice on two occasions separated by 1 week to test for repeatability. Mice were injected intraperitoneally with either 1.5 or 4.0 g/kg ethanol and the linear decline of blood ethanol level was measured. The parameters measured in each animal were linear ethanol elimination rate (EER), peak blood ethanol level, volume of distribution and Widmark ratio (r). Reproducibility was assessed using two statistical methods, paired t tests and Pearson correlations. Paired t tests indicated good reproducibility since the two replicate determinations did not differ significantly from each other. The other widely used indicator of reproducibility, the correlation coefficient (Pearson r) between the two measurements, was nonsignificant in almost every case, indicating poor reproducibility. This occurs because the range of values of EER is fairly narrow; thus, an individual is likely to fall anywhere within that narrow range from one day to the next, and the rank ordering of the individuals may not be maintained. Although parameters such as EER and volume of distribution appear to be reproducible for populations, they may have little or no utility as covariates in genetic analyses of individual differences in response to ethanol.

Animals↗

PubMed1986

Short-term memory in the macaque monkey: cue-reproducing response during delay interval.

The effects of cue-reproducing responses of macaque monkeys during the delay interval of a delayed response task were examined in several situations. The monkeys showed better performance in the cue-reproducing than the nonreproducing condition. When the monkeys were exposed to choices between two keys, responses to either key reproduced the cue, the monkeys selected the cue-reproducing key only when a "mnemonic device" was available. Cue-reproducing responses of the monkeys were suggested to correspond with human rehearsal behaviors. Codes and coding responses in delayed response performance were also discussed.

Animals↗

PubMed2004

[Interobserver reproducibility in the pathologic diagnosis of borderline ductal proliferative breast diseases].

OBJECTIVE: The aim of this study involving general pathologists was to assess interobserver reproducibility in the pathologic diagnosis of borderline ductal proliferative breast diseases. METHODS: Ten general pathologists independently reviewed 43 specimens chosen to represent the spectrum of borderline ductal proliferative breast lesions. All slides were blindly reviewed without given standardized criteria, and were classified as either mild usual hyperplasia, moderate-severe usual hyperplasia, mild atypical hyperplasia, moderate-severe atypical hyperplasia, ductal carcinoma in situ, or ductal carcinoma in situ with invasion. According to the years of training, these 10 general pathologists were divided into the experienced group and the less trained group. Interobserver agreement was statistically analyzed using Kappa statistic. Then, by comparing all the diagnoses of individual pathologist with the consensus opinion confirmed by two breast pathologists in terms of Page standard, we acquired the diagnostic accuracy and ascertained the undue diagnosis. RESULTS: The ten general pathologists' interobserver reproducibility in the diagnosis of borderline ductal proliferative breast diseases was rather low, especially that in their diagnosis of atypical hyperplasia. The reproducibility and accuracy were slightly higher in the experienced pathologists than in the less trained pathologists. Some pathologists made over-diagnosis or under-diagnosis of the lesions to different degrees. However, when the categories of diagnostic terms were simplified, the interobserver reproducibility increased. CONCLUSION: The use of standardized criteria is an important approach to increasing the diagnostic reproducibility and accuracy.

Adult↗

PubMed1985

Reproducibility and variation of morphometric analysis of carcinoembryonic antigen staining in histopathology. The influence of standardized microscopic fields.

Using morphometric methods, five pathologists analyzed the positive staining for carcinoembryonic antigen (CEA) in sections from 17 ovarian tumors, with the intraclass correlation coefficient (ICC) and the mean values of the coefficients of variation (CV) used to assess reproducibility and variation. First, field and point scores for epithelium and mucin were estimated using 25 randomly selected square fields in sections from each of the tumors. The ICC range in the whole sample field was 0.53 to 0.81 (slight to substantial reproducibility) while the mean values of CV were 0.50 to 0.75. Second, the results of using random and standardized individual fields for the measurements were studied in three tumors. In random fields, the ICC was 0.57 to 0.71 (slight to moderate reproducibility) and the mean values of CV were 0.53 to 0.65. The corresponding values in standardized fields were 0.71 to 0.73 (moderate reproducibility) and 0.41 to 0.57, respectively. The results show that the variation is smaller and the degree of reproducibility higher in standardized fields. Considerable variation remains, however, revealing human factors as an important source of variation in practical morphometry.

Carcinoembryonic Antigen↗

PubMedDate not supplied

The cytologic identification and quantification of testicular cell subtypes. Reproducibility and relation to histologic findings in the diagnosis of male infertility.

In testicular imprint smears from 100 infertile men (both testicles), stained using the Pappenheim and Papanicolaou methods, the cell forms (light and dark spermatogonia, primary and secondary spermatocytes, spermatids, spermatozoa and Sertoli cells) were identified and quantified by the counting of 500 consecutive cells. Identification of the cell types, which are described and illustrated, was consistent and reproducible; the advantages of the different stainings in their analysis is documented. The cell counts were tested for reproducibility and compared to the histologic diagnoses and sperm counts. Statistical analysis showed the highest reproducibility for cells frequently encountered in smears (0.99 for Sertoli cells and 0.98 for spermatozoa) and the lowest but still satisfactory reproducibility for rare or arbitrarily defined cell forms (0.71 for dark spermatogonia and 0.76 for secondary spermatocytes). The high reproducibility of the smear quantification permits the introduction of a number of indices, defining clinically useful relations between cell types that are indicative of various types of infertility. The data obtained by cytologic quantification showed reasonably good correlation with the histologic diagnoses of desquamation and focal fibrosis and excellent correlation with Sertoli cells only, arrested spermatogenesis and complete fibrosis. The cytologic quantification of testicular smears adds considerable information to the diagnosis of impaired fertility and should be instituted in properly equipped centers.

Cell Count↗

PubMed1993

Reproducibility of allergen-induced asthma and associated increase in bronchial responsiveness to methacholine in asthmatic children.

We studied the reproducibility of early (EAR) and late (LAR) asthmatic response to allergen challenge in 13 asthmatic children (four girls, age range: 10 to 17 years) sensitized only to Dermatophagoides pteronyssinus (Dp). Further, changes in bronchial responsiveness to inhaled methacholine following LAR were examined by measuring PC20FEV1 methacholine after 24, 48, and 72 hours. We carried out two carefully controlled allergen challenges with the same allergen dose within 4 to 6 weeks, at least 3 weeks apart, in each subject. On each study day, a bronchial challenge with methacholine was performed before and at different intervals after LAR. We found that EAR (maximal % fall in FEV1 within the 1st hour) measured on two different days was highly reproducible (37.8% +/- 8.9 and 38.7% +/- 12.1; CR: 12.1; Ri: 0.92; CoV: 15.1). Late asthmatic response (maximal % fall in FEV1 between 2nd and 12th hour) was also highly reproducible (47.5% +/- 12.4 and 46.1% +/- 13.4; CR: 10.1; Ri: 0.96; CoV: 10.1). All patients showed increases in nonspecific bronchial responsiveness to methacholine after LAR. Geometric mean PC20 M measured before the two allergen challenges was 0.609 mg/mL and 0.620 mg/mL, respectively. These values significantly decreased 24, 48, and 72 hours after LAR (after 1st allergen challenge: 0.086, 0.116, and 0.295 mg/mL; after 2nd allergen challenge: 0.075, 0.141, and 0.263 mg/mL). Ratio changes in PC20 methacholine (pre-allergen PC20 methacholine/lowest postallergen PC20) were highly reproducible (Ri: 0.95). We concluded that bronchial response to allergen challenge and the associated increase in responsiveness to methacholine are highly reproducible in well selected asthmatic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1998

Reproducibility and comparability of insulin sensitivity indices measured by stable-label intravenous glucose tolerance test.

We have investigated the reproducibility of (1) insulin sensitivity (S*I) and glucose effectiveness (S*G) as measured by the stable-label (one compartment) minimal model, and (2) insulin sensitivity (S*Ib), plasma clearance rate (PCR), basal hepatic output (HGOb), and total hepatic glucose output (HGO0-240) as measured by the novel stable-label two compartment model of glucose disappearance during labelled intravenous glucose tolerance test (IVGTT) using 6,6-(2)H-glucose. Ten normal male subjects were studied on two occasions one week apart. Both models provided estimates of all indices with acceptable precision (CV of parameter estimates < or =50%). The within subject CVs of S*I and S*Ib were comparable (17% vs 19%) as were the within subject CVs of S*G and PCR (13% vs 16%). A highly significant linear relationship was observed between S*Ib and S*I (0.303 +/- 0.046 ml kg(-1) min(-1) per mU l(-1) vs 13.04 +/- 1.89 10(-4) min(-1) per mU l(-1), y = 0.0037 x + 0.0002, r = 0.90, p < 0.001; mean +/- SE), but not between PCR and S*G (1.98 +/- 0.15 ml kg(-1) min(-1) vs 0.0089 +/- 0.0005 min(-1), rs = 0.34, NS). The two compartment model provided a plausible time-profile of hepatic glucose output during IVGTT, reproducible estimates of HGOb (1.96 +/- 0.18 mg kg(-1) min(-1), 15%; mean +/- SE, within subject CV), and a highly reproducible HGO0-240 (7%; within subject CV). We conclude that the stable-label (one compartment) minimal model and the stable-label two compartment model provide reproducible estimates of parameters of glucose kinetics in normal subjects. Insulin sensitivity indices estimated by the two models are strongly linearly related.

Adult↗

PubMed2000

Modelling the reproducibility of acoustic rhinometry.

This paper presents an application of a linear model with correlated errors to the assessment of the precision of acoustic rhinometry in clinical medicine. The design of the reproducibility study involved 20 healthy subjects measured by five investigators with three replicate measurements of four variates taken from the right and left nasal cavities, altogether 2400 measurements. The parametric model may be structured to account for random variation between subjects, serial correlation within subjects and measurement error. The model-based reproducibility correlation coefficient was estimated to be fair both for the nasal volume measurements and for the nasal minimal cross-sectional area measurements with an overall average of 0.65. An alternative measure, the within-subject coefficient of variation, averaged 15 per cent. The choice between the measures of reproducibility depends on the degree of heterogeneity of the studied populations, the presence of time trend and the scale of measurement of the rhinometric variates. In clinical practice, repeated measurements should always be made to attain a reasonable level of reproducibility in acoustic rhinometry.

Adult↗

PubMed1997

Intralaboratory quality assurance in cervical/vaginal cytology: evaluation of intercytologist diagnostic reproducibility.

Diagnostic reproducibility and accuracy in evaluating cervical/vaginal smears were the focus of this study concerning intralaboratory quality control. A set of 120 cytological samples was evaluated by 15 cytopathologists whose experience ranged from 3-29 yr. The study report form was based on the 1988 Bethesda System. Intercytologist reproducibility (with respect to sample adequacy, epithelial cell abnormalities, and presence of cellular changes associated with HPV, Human Papilloma virus) was evaluated using the Kappa statistic. Poor reproducibility in defining sample adequacy was observed (K = 0.24). The agreement on epithelial cell abnormality definition was good (K = 0.64); the lowest reproducibility was observed for High-grade squamous intraepithelial lesion/cervical intraepithelial neoplasia HSIL/CIN II (specific K = 0.37) and Atypical cells of undetermined significance ACUS (specific K = 0.44). The agreement in detecting cellular changes associated with HPV was fair (K = 0.49). Diagnostic accuracy for epithelial cell abnormalities, assessed by comparison with a consensus reference diagnosis, was good (K = 0.74).

Cervix Uteri↗

PubMed2000

Statistical motor unit number estimation: reproducibility and sources of error in patients with amyotrophic lateral sclerosis.

The reliability of motor unit number estimation (MUNE) for assessment of the long-term course of ALS is dependent on the reproducibility of the technique. We report our results with the statistical method of MUNE on the ulnar nerve/hypothenar muscle in 16 ALS patients who were studied on 52 occasions. On each occasion, MUNE was performed twice with one electrode placement and once with a different placement. For each MUNE, mean surface motor unit potential amplitude was determined within three different recording ranges or windows at different stimulus intensities. The MUNE results had excellent reproducibility with coefficients of variation of 19% and test-retest correlation coefficients from 0.75 to 0.86. With examination of sources for variability, the reproducibility of statistical MUNE is not affected by minor variation in stimulation and recording electrode placement but may be improved by modifying methods for recording window selection. The high reproducibility of statistical MUNE supports its reliability for estimating the rate of motor unit loss in ALS.

Algorithms↗