[Quality control. II. Patient averages in the quality control of serum electrolyte measurements].
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In the present era of expanding technology coexisting with economic constraint, appropriate quality control criteria to monitor laboratory performance must take into consideration not only analytic precision and medical utility, but also cost effectiveness. In this review, the effect of existing criteria on the clinical laboratory, the regulator, and the vendor is explored. Factors that contribute to excessive quality control cost are delineated. Strategies for developing a cost-effective quality control program are proposed.
Experience and research over the last twenty years has shown that an organised team approach is needed to reduce hospital acquired infection and prevent outbreaks. This team must be able to influence the behaviour of health care workers and can be compared with the work of quality control in an industry. Much more emphasis is now placed on the measurement of quality of care. The Japanese are to be commended for their 'quality circle' approach which has certainly changed the attitude of the rest of the world to the 'Made in Japan' label.
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Quality control (QC) data of radiotherapy linear accelerators, collected by Helsinki University Central Hospital between the years 2000 and 2004, were analysed. The goal was to provide information for the evaluation and elaboration of QC of accelerator outputs and to propose a method for QC data analysis. Short- and long-term drifts in outputs were quantified by fitting empirical mathematical models to the QC measurements. Normally, long-term drifts were well (< or =1%) modelled by either a straight line or a single-exponential function. A drift of 2% occurred in 18 +/- 12 months. The shortest drift times of only 2-3 months were observed for some new accelerators just after the commissioning but they stabilized during the first 2-3 years. The short-term reproducibility and the long-term stability of local constancy checks, carried out with a sealed plane parallel ion chamber, were also estimated by fitting empirical models to the QC measurements. The reproducibility was 0.2-0.5% depending on the positioning practice of a device. Long-term instabilities of about 0.3%/month were observed for some checking devices. The reproducibility of local absorbed dose measurements was estimated to be about 0.5%. The proposed empirical model fitting of QC data facilitates the recognition of erroneous QC measurements and abnormal output behaviour, caused by malfunctions, offering a tool to improve dose control.
Brucella broth without supplementation is the recommended medium for broth microdilution susceptibility tests of Brucella abortus, B. melitensis, and B. suis. Based on an eight-laboratory collaborative study using a pH-adjusted modification of this medium, we propose MIC quality control ranges for three control strains against 10 antimicrobials that are potentially efficacious for treating infections caused by these agents of bioterrorism.
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This paper reports results of a first phase of a pilot study to assess and improve quality of diagnoses in cervical cytological laboratories located throughout Italy. It represents the first phase of an External Quality Assurance programme (EQA). In the first phase, two sets of cervical smears representing a range of diagnoses were circulated among participating laboratories. Responses were recorded on a standardized form. Participants were asked to assess the adequacy of the smear and formulate a diagnosis. They were also asked to recommend management of the patient on the basis of the smear report and judge the degree of diagnostic difficulty of each slide. Crude index of agreement, unweighted and weighted kappas, diagnostic specific kappas, sensitivity and specificity as well as clinical indices of variability were calculated. In the second phase, two additional sets of slides were circulated after discussion of the first phase. There was striking variability between laboratories, both in terms of diagnoses offered and recommendations for management on individual slides. Assessment of the degree of difficulty of each slide was also very variable. Discrimination between CINII and CINIII was poor, confirming the choice of merging these two categories in the Bethesda classification. However, discrimination between CINI and CINII was also unsatisfactory. The results were discussed in workshops and it was possible to reach a consensus diagnosis in 35 of 40 smears. This study confirms the need for external quality control programmes.
OBJECTIVE: To investigate the adequacy of bedside glucose monitoring (BGM) quality control documentation and monitoring, characterize program structure and organization, and identify characteristics associated with the ability to produce accurate results. DESIGN AND SETTING: College of American Pathologists Q-Probes laboratory quality improvement study in 544 institutions. MAIN OUTCOME MEASURES: Percent compliance with quality control (QC) documentation, appropriate corrective action, and frequency of inappropriate patient testing, and the percentage of BGM results within +/-10% and +/-15% of a corresponding clinical laboratory glucose result. RESULTS: Five hundred forty-four institutions reviewed a total of 19543 individual QC paper documents from 2543 separate BGM instruments. Ninety percent of QC determinations that should have been performed and noted on these documents were recorded; of those performed, 2.8% of QC results were outside of the acceptable range. Thirty-two percent of the out-of-range QC results had no record of corrective action. There were 527 reported instances of one or more patients being tested when there was no record of corrective action for out-of-range QC results. There were 20665 undocumented potential QC events, with 2053 instances of one or more patients being tested when there was no documentation. Two hundred forty-two institutions submitted 6653 paired BGM and clinical laboratory results for comparison. Approximately 56% of BGM results were within +/-10%, and 74% were within +/-15% of the corresponding clinical laboratory result. Factors associated with better accuracy performance are discussed. CONCLUSIONS: There is a need for improving compliance with QC documentation, improving appropriate corrective action follow-through, decreasing the frequency of inappropriate patient testing, and improving BGM accuracy performance. We provide recommendations for improvement.
PURPOSE: Quality assessment and assurance are important issues in modern health care. For the evaluation of surgical procedures, there are indirect parameters such as complication, recurrence, and survival rates. These parameters are of limited value for the individual surgeon, and there is an obvious need for direct parameters. We have evaluated criteria by which pathologists can judge the quality or completeness of the resection specimen in a randomized trial for rectal cancer. PATIENTS AND METHODS: The pathology reports of all patients entered onto a Dutch multicenter randomized trial were reviewed. All participating pathologists had been instructed by workshops and videos in order to obtain standardized pathology work-up. A three-tiered classification was applied to assess completeness of the total mesorectal excision (TME). Prognostic value of this classification was tested using log-rank analysis of Kaplan-Meier survival curves using the data of all patients who did not receive any adjuvant treatment. RESULTS: Included were 180 patients. In 24% (n = 43), the mesorectum was incomplete. Patients in this group had an increased risk for local and distant recurrence, 36.1% v. 20.3% recurrence in the group with a complete mesorectum (P =.02). Follow-up is too short to observe an effect on survival rates. CONCLUSION: A patient's prognosis is predicted by applying a classification of macroscopic completeness on a rectal resection specimen. We conclude that pathologists are able to judge the quality of TME for rectal cancer. With this direct interdisciplinary assessment instrument, we establish a new role of the pathologist in quality control.
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A computer simulation program has been developed to aid clinical chemists in the design and theoretical evaluation of statistical control procedures. This "QC simulator" permits the user to study the effects of different parameters characterizing the measurement procedure (method standard deviation, components of variation, rounding of results) and parameters of the control procedure (decision criteria, control limits, number of observations). The performance of control procedures is characterized by the probability for rejection, estimated at several different levels of random and systematic error. Predictive values for reject and accept signals are also calculated at different error incident rates, given a specified error model. The relative performance of different control procedures can be compared based on these performance characteristics. Another important application of the program is the design of control procedures to assure that a specified level of analytical quality is achieved in routine analyses. Various optimization criteria may be applied, e.g., in terms of test yield and cost.
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Multirule quality control procedures employ combinations of individual quality control rules to increase the probability of error detection without increasing the probability of false rejections to unacceptable levels. Performance characteristics of several example multirule procedures are described, and general recommendations are made for their selection and use. Multistage quality control procedures tailor the control rules employed to the frequency of errors expected during a given phase of analyzer operation. During analyzer startup, sensitive rules are employed; after acceptable analyzer performance is demonstrated, less sensitive rules are used for routine monitoring. As they tend to deteriorate quality control rule performance, between-run variations should be minimized.
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