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At least 1,261 records · Page 70Linked to original sources
PubMed1991

Dosage accuracy of self-mixed vs premixed insulin.

The accuracy of patients and health care professionals in drawing up the components of a split-mix insulin regimen and of premixed insulin at three dosages (30 units, 10 units, and 5 units) was assessed with both 30-U and 100-U syringes. Both patients and professionals were inaccurate with both syringes. At low doses tested and with both syringes, patients and professionals showed greater accuracy with premixed insulin than with self-mixed insulin. Errors in drawing up insulin involved errors mainly in the ratio rather than the total volume of insulin drawn. Accuracy improved with higher doses of insulin. The patients' perception of their skill level in drawing up and mixing insulin correlated with the objective measurements of their skill. The improved accuracy in dosing with premixed insulin might explain the previously observed improved glycemic control in patients taking premixed insulin.

Adult↗
PubMed1991

The accuracy and precision of the third mandibular molar as an indicator of chronological age.

The study was designed to investigate the accuracy and precision of the development of the third mandibular molar, determined on panoramic x-rays, as an indicator of chronological age- a method which is used in Sweden to estimate chronological age in certain young foreign individuals with uncertain birth records. Accuracy test: The mean difference between the estimated and true chronological age was determined in a sample of 372 14.5-24.5-year-old subjects. The data were arranged in subgroups according to sex and age. The accuracy test showed a systematic underestimation of age, increasing with age in both sexes. The 95 per cent confidence interval of the difference between estimated and true chronological age was large, about +/- 4.5 years in girls and +/- 2.8 years in boys. The association between dental age and chronological age, expressed in correlation coefficients, was poor. Precision test: The intra-examiner error was low but the 95 per cent confidence interval of the difference was large, +/- 0.8 years. The dental development of the third mandibular molar should not be used for estimation of chronological age in individual subjects, due to its very low accuracy.

Adolescent↗
PubMed1989

[On the assessment of the diagnostic accuracy of imaging diagnosis by ROC and BVC analyses--in reference to X-ray CT and ultrasound examination of liver disease].

To achieve an effective assessment of diagnostic accuracies of currently used imaging methods on liver diseases, X-ray CT (CT) and realtime ultrasound (US), ROC analysis and a new analysis method, "the bias to variance characteristics (BVC)" were applied in parallel. The survey has been carried out to assess an image interpretation accuracy on cases with established diagnosis collected on the multi-institutional basis. The images, CT and US of liver diseases including localized and diffuse lesions were selected for image reading sessions and the interpretative difficulties were geared to an appropriate grade so that it does fit to the basic requirement of ROC analysis. Consequently, 91 cases were selected from a total of 258 cases which were collected from 16 institutions. Two image reading sessions were scheduled and a total of 28 radiologists and sonologists undertook the first session. The final analysis covered 8 radiologists for CT and 9 sonologists who carried out both sessions. The image interpretation results were fed to the computer and analyses were made accordingly. Analysis of the first image reading session gave true positive ratios (TPR) of CT and US as 92.5% and 97.4%, and true negative ratios (TNR) of 50.5% and 46.8%, respectively. The second reading session, in which both CT and US images were interpreted simultaneously, gave the similar values of TPRs, 96-97% and TNRs, 44-47%. The ROC analysis of existence of liver mass and diagnosis of malignancy resulted in the higher values in US compared to CT in the first separate reading, however, the 2nd session gave almost identical values in each modality. The diagnostic accuracy for the benign tumors, mostly consisted of hemangioma, CT reading gave higher accuracy rates compared to the US. The entirely new interpretations scheme, arbitrarily named as BVC was carried ou on matrix data obtained in the same experiment. The scatterograms plotted according to the BV values, the mean and the standard deviation inherent to individual cases have demonstrated marked variations among individual cases most likely reflecting the interpretative difficulty of respective images, thus indicating the method to be well in adjunct to the ROC analysis.

Adult↗
PubMedDate not supplied

Statistical measurements of accuracy in cervical cytology.

Statistical measures that can be used to monitor the level of accuracy of cervical cytologic screening are examined: sensitivity, the false-negative rate, the interval cancer rate among women with negative reports and the predictive value of a positive test. Sensitivity and the false-negative rate are subject to biases and problems of determination that may make them less useful as measures of accuracy. The interval cancer rate and the positive predictive value may be better methods of assessing the frequency of serious abnormalities following negative cytologic reports and the accuracy of cytologic reports of serious abnormalities, respectively. It is important to recognize that no single measure of accuracy can adequately define a laboratory's performance. The use of statistical analyses can be invaluable in placing in context the criticisms of cervical cytology as an appropriate screening test for the prevention of cervical cancer; statistical analysis should be used as one component of quality control.

Cervix Uteri↗
PubMed1988

Accuracy of duplex scanning in the detection of stenosis after carotid endarterectomy.

The results of duplex ultrasonography in grading stenosis after carotid endarterectomy (78 sites) were compared with those of contrast angiography in 71 patients studied for recurrent or contralateral occlusive disease of the carotid bifurcation. Duplex and angiographic studies were performed within one month of each other at a mean postoperative interval of 44 months (range 3 to 122 months). Stenosis of the common carotid (CCA) and internal carotid artery (ICA) was classified into five disease categories (normal or less than 15% diameter reduction [DR], 16% to 49% DR, 50% to 75% DR, greater than 75% DR, and occlusion). The overall accuracy of duplex scanning compared with angiography in predicting recurrent carotid bifurcation disease was 83%, a level of agreement similar to classification of disease involving the nonoperated, contralateral bifurcation (overall accuracy 87%). Recurrent stenosis (greater than 50% DR) or occlusion of the CCA or ICA after endarterectomy was identified with an accuracy of 97%. Overestimation of severity of recurrent stenosis accounted for 11 of 13 duplex classification errors (85%). Presence of moderate (30% to 50% DR) recurrent stenosis of the CCA, tortuosity of the ICA, and severe contralateral carotid bifurcation disease were associated with velocity spectra that predicted a more severe recurrent stenosis at the endarterectomy site compared with angiographic grading. The level of agreement between duplex scanning and angiography was comparable to the interobserver variability in angiographic interpretation. The accuracy reported justifies the use of duplex scanning to grade the severity of carotid bifurcation recurrent stenosis and to follow these lesions for disease progression.

Carotid Artery Diseases↗
PubMed1988

The how and why of an accuracy base for proficiency testing programs.

The National Bureau of Standards (NBS) has been involved for more than ten years in development of definitive methods for measuring important inorganic and organic analytes in human serum, including calcium, potassium, chloride, cholesterol, glucose, urea, uric acid, and creatinine. These methods are carefully designed and thoroughly tested isotope dilution mass spectrometric procedures that produce results of high precision and accuracy. Definitive methods are used to certify concentrations in reference serum pools, which are distributed among clinical laboratories as a means of assessing the accuracy of the routine methods. The College of American Pathologists operates a major proficiency testing program for clinical laboratories. The National Bureau of Standards works with the College of American Pathologists to assign values for analyte concentrations in proficiency testing samples where possible, and these values are used to assess the overall accuracy of the participants (grand mean) as well as the accuracy of peer groups (those that use the same methodology and/or instrumentation). For the analytes studied to date, the grand mean values have generally been close to the definitive values, but some of the peer group results have shown significant biases. To illustrate the definitive method development process, a modified and improved definitive method for cholesterol measurement is described. The modified method uses a cholesterol-13C3 as the labeled internal standard, capillary gas chromatography for sample introduction, and a novel means of electrically switching between the ions being measured. Results on standard reference material 909, a lyophilized human serum, demonstrate the precision and absence of significant measurement bias attainable with the new method.

Academies and Institutes↗
PubMed1988

Evaluation of the clinical accuracy of laboratory tests.

Fundamental clinical performance of a laboratory test can be described in terms of accuracy, or the ability to correctly classify subjects into clinically relevant subgroups. Accuracy refers to the quality of the information provided by the classification device and should be distinguished from the efficacy, or practical usefulness, of the information. Receiver operating characteristic curves provide a pure index of accuracy by demonstrating the limits of a test's ability to discriminate between alternative states of health over the complete spectrum of operating conditions. If analytical imprecision is removed from the data, the resulting receiver operating characteristic curve represents the inherent biological variation that ultimately limits the clinical accuracy of the test.

Diagnostic Tests, Routine↗
PubMed1986

Accuracy of piezoelectric accelerometers measuring displacement of a spinal adjusting instrument.

The accuracy and reproducibility of an electronic system to measure the displacement of a spring-loaded chiropractic adjusting instrument was examined. The electronic system included a piezoelectric force transducer, piezoelectric accelerometer transducers and a digital oscilloscope. Accuracy was studied by comparing electronic measurements with the expansion allowed by the mechanically limiting expansion-control knob of the instrument. The results suggested improvements for future accuracy verification checks and detected accuracy within about 10% of the expansion of the commonly used expansion-control-knob revolutions. Preliminary experiments are presented to show application of the system to studies on thrusts into the spine. The impedance-head-equipped spring-loaded Activator chiropractic adjusting instrument had a low velocity when used on the patient and appeared to cause bone movement and a measurable EMG response.

Animals↗
PubMed1986

Weight control content of women's magazines: bias and accuracy.

In order to assess the quality of weight control information directed at women through popular magazines, 37 issues on newsstands in January, 1982, were examined. Issues selected included approximately equal numbers of the top sellers, diet and exercise magazines, and newly established women's magazines as well as a smaller number of 'teen' magazines. The 67 articles on weight control found were evaluated by three nutritionists using a semantic differential scale based on Allon's four areas of discrimination against obesity and a 14-item test for accuracy. The 'diet' magazines devoted the highest portion of pages to weight control information, followed by the teen, top-seller, and new woman magazines in that order. Almost one-third of the articles scored perfect on accuracy of the information included; 15 percent were judged uncertain or worse. The remainder were judged largely, but not completely accurate. Judges found the articles were slightly skewed toward the negative ends of the scales assessing bias. Only 11 percent of the articles were judged pessimistic regarding success in weight control. The accuracy of this optimism must be questioned. There were no differences in accuracy, bias, or optimism among the four types of magazines.

Adolescent↗
PubMed1986

The accuracy of children's self-reports of diet: Family Health Project.

This study was designed to test the accuracy of four different methods for enabling children in the third to sixth grades to record their frequency of consumption of foods high in any of four targeted nutrients. The forms varied in two ways: recording the whole day or a segment of the day (morning, afternoon, or evening) or use or non-use of pictures of the food items. The accuracy of the children's recording of food consumption was validated by observation of their behavior for 2 continuous 12-hour days. Twenty-four children in the third to sixth grades were observed for each of the 2 days. An 82.9% agreement was obtained between the child's self-reported food frequency and the observer's record of the child's consumption. Ethnicity slightly affected the accuracy of form completion, while gender and grade level of the children did not. The results of this study validate the accuracy with which children record diet using a food frequency of consumption method.

Child↗
PubMed1985

Antibiotic susceptibility testing accuracy. Review of the College of American Pathologists Microbiology Survey, 1972-1983.

The antibiotic susceptibility testing results for the College of American Pathologists' Microbiology Surveys subscribers for 1981 to 1983 were compared for accuracy and problem areas with earlier data dating back to 1972. Disk diffusion (Kirby-Bauer) test accuracy was 96.3%, 96.4%, and 95.0% for the Bacteriology, Comprehensive, and Basic Surveys participants, respectively. The overall dilution test and automated system (Autobac I) accuracy was 95.8% and 93.8%, respectively. More laboratories (more than 40% of bacteriology and comprehensive laboratories) were using dilution minimum inhibitory concentration tests, usually frozen-form commercial systems. The current test accuracy was comparable with data for previous years, but the Basic Survey subscribers have demonstrated improvement since mid-1981. Several testing problems were identified, principally in the interpretive criteria available in national consensus publications such as the National Committee for Clinical Laboratory Standards M2-A3. Many of these problems have recently been resolved through the cooperation of the National Committee for Clinical Laboratory Standards' subcommittees and the College of American Pathologists' surveys.

Anti-Bacterial Agents↗
PubMed1984

Accuracy of aspiration cytology in detecting breast cancer.

To evaluate the role of needle placement in determining accuracy and to establish criteria for clinical decision making, we used aspiration cytology to diagnose 49 palpable breast masses in patients undergoing excisional biopsy. Closed cytology, obtained by percutaneous aspiration, and open cytology, obtained by aspiration of the excised mass, were compared with histology. Nineteen (39%) of the breast masses were carcinoma. Unsatisfactory cytologic findings were frequent after both closed (37%) and open (24%) aspiration. Most of these aspirates were from mammary dysplasia, suggesting that acellularity rather than needle placement was responsible. Closed aspiration was falsely negative in one patient and falsely suggestive of cancer in five. If atypical, suspicious or malignant cytologic findings were considered to be carcinoma; closed cytology had high sensitivity (94%), low specificity (64%), and a false positive fraction of 36%. The positive predictive value was 76% and the negative predictive value 90%. Accuracy was 81%. If only suspicious or malignant results were considered positive, specificity and positive predictive value increased at the expense of sensitivity and negative predictive value but accuracy did not change. Even with optimal needle placement (open aspiration), accuracy of aspiration cytology was less than 90%.

Biopsy, Needle↗
PubMed1983

The accuracy of reports of weight: children's recall of their parents' weights 15 years earlier.

This report describes the accuracy with which adults can recall the weights of their parents as they were 15 yr before. In 1962-65, measurements of height, weight and skinfold thickness were made in the Tecumseh Community Health Study. In 1979, 134 children of 96 mothers and 117 children of 79 fathers were asked to recall their parents' heights and weights at the earlier time and to select one of nine outline drawings, ranging from very thin to very fat, which best represented the parents at the time they were measured. The correlation between body mass index [weight in (kg)/height2 in (m)] as reported and as measured was 0.82 for mothers and 0.56 for fathers. Similar correlations were found between the selected figure and the measured body mass index: 0.74 for mothers and 0.63 for fathers. Measured values in the high range were underestimated, those in the low range were overestimated. Adding the figure selection to the report of height and weight increased the accuracy of estimation, particularly for fathers. Reports of height and weight and of figure selection were more highly correlated with measured body mass index than with skinfold thickness. None of several characteristics of the offspring had any major influence on the accuracy of their reports: age, sex, height, body mass index, skinfold thickness or the confidence of the subject in his ability to remember. Accuracy of the reports was similarly not related to age or height of the parent or to the report of the other parent's weight. We conclude that offspring reports of their parents' past weight may be a useful epidemiological tool.

Adolescent↗
PubMed1995

Accuracy of clinicians in predicting site and type of lesion as well as outcome in horses with colic.

OBJECTIVE: To assess the ability of clinicians to predict the site and type of lesion as well as outcome in horses with colic. DESIGN: Prospective case study. SAMPLE POPULATION: 139 horses admitted for evaluation of signs of colic. PROCEDURE: Six interns and residents examined horses with colic and predicted the segment of intestine that was affected, the type of lesion, and whether the horse would survive to discharge. Accuracy of prediction of site and type of lesion and survival prediction was compared between the first and second halves of the year, using chi 2 analysis and 95% confidence intervals on sensitivity and specificity. chi 2 Analysis was used to assess accuracy between predicted site and type of lesion and intraoperative or necropsy findings and to assess accuracy between predicted survival and actual outcome. RESULTS: Significant association existed between predicted segment of affected intestine or type of lesion and intraoperative findings (P < 0.05). There was a significant association between predicted survival and outcome (P < 0.001). Accuracy of survival prediction improved significantly (P = 0.002) during the year. CLINICAL IMPLICATIONS: Clinicians can accurately predict horses with colic that will survive surgery on the basis of clinical impressions. The ability to predict those horses that will survive improves with training.

Animals↗
PubMed1995

Transcranial magnetic stimulation of the posterior parietal cortex degrades accuracy of memory-guided saccades in humans.

PURPOSE: Previous neurophysiological studies in the monkey have shown that the posterior parietal cortex (PPC) is involved in the control of memory-guided saccades. In this study, the authors investigated the effect of focal transcranial magnetic stimulation (TMS) over the posterior parietal cortex on accuracy of memory-guided saccades in humans to clarify the cortical region related to controlling memory-guided saccades. METHODS: Single TMS pulses were applied systematically at various locations over the parietal cortex during memory-guided saccades in human subjects. Each subject was instructed to fixate on a central target until the target was extinguished. A lateral target was flashed for 100 msec with unpredictable direction and amplitude. The subject executed a saccade to the remembered position of the previously flashed target in total darkness when the central target was extinguished. Transcranial magnetic stimulation was applied after the extinction of the central target with various latencies. Stimulation sites were identified by three-dimensional magnetic resonance imaging (MRI). RESULTS: Transcranial magnetic stimulation of the right PPC degraded accuracy of rightward and leftward memory-guided saccades in all subjects, when TMS was applied 100 msec after the offset of the central target. On the other hand, TMS of the left PPC showed no effects on accuracy of memory-guided saccades. Systematic error of saccade amplitude appeared as a hypometria for rightward saccades. Three-dimensional MRI revealed that the effective stimulation site was located over the posterior portion of the intraparietal sulcus and the superior part of the angular gyrus of the right hemisphere. CONCLUSIONS: These findings strongly suggest that the right PPC is involved in maintaining spatial accuracy of remembered target locations of memory-guided saccades in humans.

Adult↗
PubMed1994

A retrospective study of the diagnostic accuracy of a community hospital-based PET center for the detection of coronary artery disease using rubidium-82.

UNLABELLED: A retrospective analysis has been carried out to determine the diagnostic accuracy of PET of the heart with 82Rb at a community hospital based center. METHODS: Utilization statistics were derived from a total of 1460 patients scanned for the first 36 mo of the center's operation. Diagnostic accuracy for detection of coronary artery disease (CAD) was assessed using three readers blinded to the clinical information. A total of 287 rest and dipyridamole-stress scans of patients who had coronary angiograms within 6 mo of the PET scan were selected by the computer for this study. Each rest/stress scan was read by at least two of the three readers. RESULTS: The average sensitivity for all three readers was 87% for greater than 67% diameter stenosis and the average specificity was 88% for myocardial regions perfused by normal coronary arteries. The average accuracy was 88% for patients with greater than 67% diameter stenosis. Sensitivity and accuracy improved to 92% and 91% respectively for stenosis greater than 90% in diameter. CONCLUSION: These results compare well with published results from major hospital-based centers and the recently published results from a private PET center in Georgia.

Coronary Angiography↗
PubMed1994

[Adding atropine improves the diagnostic accuracy of dipyridamole-echo test].

BACKGROUND: The clinical experience with dipyridamole stress echocardiography for the diagnosis of coronary artery disease (CAD) revealed that patients with less severe extent of CAD and limited impairment of coronary reserve are frequently not recognized by the test. Increasing myocardial oxygen consumption adding atropine to dipyridamole may improve the diagnostic accuracy of dipyridamole for the detection of CAD. METHODS: Fifty-two patients (48 men, aged 53 +/- 7 years) underwent a high-dose dipyridamole-echo stress test (0.84 mg/kg over 10 minutes) and coronary arteriography within 15 days from the test. Eighteen out of 52 patients were referred for chest pain; 11 suffered from a previous myocardial infarction (MI) and 23 were studied in the early phase after a first acute MI. Starting after 4 minutes from the end of dipyridamole infusion, atropine was added, in 2 doses of 0.5 mg each, at 1-minute interval in those patients with no echocardiographic evidence of myocardial ischemia after dipyridamole alone. Left ventricular wall motion was analyzed on a 11-segment left ventricular model in a qualitative manner. RESULTS: Dipyridamole-echo stress test was positive in 23/52 (44%) and negative in 29/52 (56%) patients. In these patients atropine was added resulting in an additional echo positivity in 14/29 patients. Coronary arteriography was normal in 6 patients (12%); 1-vessel CAD was diagnosed in 23 (44%), 2-vessel CAD in 13 (25%) and 3-vessel CAD in 10 (19%) cases. The sensitivity for CAD diagnosis was 48% (22/46) for dipyridamole alone and 76% (35/46) for dipyridamole-atropine echo (p < .005), while the specificity was 83% (5/6) and 80% (4/5) respectively. Diagnostic accuracy increased from 52% (27/52) to 75% (39/52) (p < .001). The better diagnostic accuracy of dipyridamole-atropine echo stress test was mainly related to the increased sensitivity of the combined test in patients with 1-vessel CAD (from 39% to 70%) (p < .005). Peak heart rate was significantly higher after the addition of atropine (100 +/- 17 beats/min) compared to basal (64 +/- 10) and dipyridamole (85 +/- 12) in those patients with a positive dipyridamole-atropine echo stress test. No limiting side effects were elicited with the addition of atropine to dipyridamole. CONCLUSIONS: The combination of atropine and dipyridamole induces a chronotropic stress adjunctive to flow maldistribution phenomena that permits to increase diagnostic accuracy of dipyridamole-echo stress test particularly in patients with less severe extent of CAD; it is usually well tolerated and safe and may be considered as a useful procedure for optimizing diagnostic value of dipyridamole-echo stress test.

Aged↗
PubMed1994

Accuracy of correction of complex lower-extremity deformities by the Ilizarov method.

Gradual mechanical distraction with the Ilizarov external fixator was used on 28 limbs in 23 patients to correct complex lower-extremity deformities of diverse causes. To determine the accuracy of realignment and deformity correction, the charts and radiographs were reviewed retrospectively. Preoperative long-standing anteroposterior radiographs of the entire lower extremity were compared with those obtained at the most recent follow-up visit. The parameters used to assess accuracy of correction were joint alignment and joint orientation. Alignment was determined by mechanical axis deviation (MAD) and mechanical tibiofemoral angle (mTFA). The preoperative MAD averaged 48 mm and the postoperative MAD 8.6 mm. The preoperative mTFA averaged 16 degrees and the postoperative mTFA 3 degrees. The result of deformity correction from early cases was compared with the result obtained from recent cases. Residual MAD averaged 13.2 mm in the early group and 6.4 mm in the recent group. Residual mTFA averaged 4.7 degrees in the early group and 2.2 degrees in the recent group. Gradual correction by dynamic external fixation can restore alignment and correct complex deformities with great accuracy. These results suggest the accuracy of correction increases with surgical experience.

Adolescent↗