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PubMed1994

[Primary quality control in Israel Air Force clinics].

The practice of primary medicine within a military framework differs from that in the civilian environment in: accessibility, its consumers, obligations of the providers, involvement of the funder (the commanders), and ability to define and enforce professional guide lines. These differences influence the scope of medical service, as well as affect the methods and results of quality control. A system of quality control evaluation and feedback of military primary care in 16 Israel Air Force clinics was carried out by a team of experienced physicians using peer group review and according to a specially prepared protocol. Emphasis was placed on medical record assessment using obligatory markers of adequate medical evaluation and treatment. Identification of the population at risk, further medical training, and medical administration with a direct effect on the quality of medical treatment were also evaluated. 2 quality control surveys with feedback were carried out 6 months apart. The overall mean score was 81.66 +/- 7.16% at the first evaluation, increasing to 88.60 +/- 7.46% at the second (p < 0.01). The greatest improvements were in follow-up of population at risk (increasing from 68.4% to 86.4%, p < 0.025), training of medical teams, (from 75.7% to 87.5%, p < 0.05) and patient case management (from 79.4% to 85.1%, N.S.). Categories in which there was no improvement were medical records, recovery of old medical files and patient education. The categories in which there was improvement had a common denominator: "recognition of importance" and "provision of patterns" by headquarters. The quality control system was designed for routine use, and not as a research project.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerospace Medicine↗
PubMed1990

Evaluation of a commercial diode monitor for mailed quality control of therapy units.

A commercial diode dosimeter was evaluated for use in a mailed radiotherapy quality control package. The quality control package contained the commercial diode dosimeter and four thermoluminescent dosimeters to measure the given dose, and it also contained a photographic film to measure the light/radiation field coincidence. The film also served as a backup dosimeter. Twenty small Midwestern hospitals participated in field measurements; approximately half of the hospitals had a consulting physicist and the others had one full-time physicist. Each hospital was asked to deliver 1.5 Gy (150 rads) to the device, which was returned to our laboratory for evaluation. Reliable results were obtained from three measurements at each hospital at about 3-month intervals. The diode dosimeter was more precise than thermoluminescent dosimeters or film.

Calibration↗
PubMed1990

Quality control of multichannel haematology analysers: critique of current methods and the need for performance goals.

Performance goals for internal quality control of multichannel haematology analysers have been developed by consensus in the Subcommittee on Quantitative Cellular Haematology of the National Committee of Clinical Laboratory Standards (NCCLS). Conventional methods of quality control (i.e. use of standards for machine calibration and control samples to detect drift) are not feasible for the automated complete blood-cell count because standards and generally accepted reference methods for cell enumeration are not currently available. In the absence of an ideal system, a host of different quality control strategies are utilized with fresh whole blood, stabilized blood preparations, commercial surrogate materials, and statistical functions of measurements on patient specimens. All have their theoretical strengths and weaknesses which, up to now, have been difficult to quantify and to compare experimentally between methods and between laboratories. Performance goals, or what have been judged by a consensus of experts to be achievable tolerance limits for the various sources of analytical variations, were determined for the following measurements: haemoglobin concentration, erythrocyte count, leukocyte count, platelet count, and mean cell volume. These performance goals can be used to compare the effectiveness of the various quality control strategies now used and to determine which strategy would perform best and be most cost-effective in a particular laboratory situation.

Automation↗
PubMed2003

A special ionisation chamber for quality control of diagnostic and mammography X ray equipment.

A quality control program for X ray equipment used for conventional radiography and mammography requires the constancy check of the beam qualities in terms of the half-value layers. In this work, a special double-faced parallel-plate ionisation chamber was developed with inner electrodes of different materials, in a tandem system. Its application will be in quality control programs of diagnostic and mammography X ray equipment for confirmation of half-value layers previously determined by the conventional method. Moreover, the chamber also may be utilised for measurements of air kerma values (and air kerma rates) in X radiation fields used for conventional radiography and mammography. The chamber was studied in relation to the characteristics of saturation, ion collection efficiency, polarity effects, leakage current, and short-term stability. The energy dependence in response of each of the two faces of the chamber was determined over the conventional radiography and mammography X ray ranges (unattenuated beams). The different energy response of the two faces of the chamber allowed the formation of a tandem system useful for the constancy check of beam qualities.

Equipment Design↗
PubMed2000

Quality control of test systems waived by the Clinical Laboratory Improvement Amendments of 1988. Perceptions and practices.

CONTEXT: Recent advances in laboratory testing technology have resulted in a rapidly increasing number of test systems targeted for physician office, point-of-care, and home health care settings. With enhanced error detection mechanisms and unitized reagents, these new systems simplify the testing process and the assessment of analytical test performance. Many also meet the criteria set by the Clinical Laboratory Improvement Amendments of 1988 (CLIA) to qualify as waived test systems, and laboratories using only waived tests are subject to very limited regulatory oversight. OBJECTIVE: To evaluate use patterns and perceptions about quality control requirements with respect to waived testing. DESIGN AND SETTING: Survey of a network of 431 hospital, independent, and physician office laboratories in the US Pacific Northwest. RESULTS: Responding laboratories (n = 221) were taking advantage of the availability of waived tests and using them to make definitive diagnoses. We found considerable differences between quality control practices and the laboratories' perceptions of quality control requirements. Most respondents were performing traditional quality control on waived tests, influenced by their interpretation of regulations, the intended use of the test, and the testing personnel employed. CONCLUSIONS: Technology optimized for alternate quality control can represent an improvement in ease of use while meeting expectations for accuracy and providing relief from regulatory burdens. However, laboratory personnel exhibit confusion in applying new quality control systems.

Attitude of Health Personnel↗
PubMed1976

Quality control in clinical chemistry: the essential steps.

Assurance of the quality or reliability of test results is the responsibility of the laboratory and the concern of the veterinarian who uses these results in the diagnosis or treatment of animal patients. Quality assurance can be produced only by implementation and continuing maintenance of a quality control program to monitor the daily performance of the laboratory. Quality control programs usually are multifaceted and may be comprised of one or several optional components. An essential ingredient in any program designed to provide quality assurance is the "quality-awareness" of those who perform the tests or make clinical use of the test results.

Blood Urea Nitrogen↗
PubMed1992

Assuring analytical quality through process planning and quality control.

United States governmental regulations describe quality assurance as a system in which quality control (QC) and proficiency testing are to be used to substantiate that routine tests conform to specified performance criteria. Careful planning of analytical processes is necessary to guarantee that routine tests will achieve the analytical performance defined by the Health Care Financing Administration proficiency testing criteria. These proficiency testing criteria are analytical "total error" requirements that need to be translated into operational process specifications for the allowable imprecision, allowable inaccuracy, and the QC procedure (decision rules, number of control measurements) necessary to provide a known or specified level of analytical quality assurance. The level of assurance will depend on the QC procedure's probability for detecting critical sized errors that would cause the quality requirement to be exceeded. Analytical quality can be guaranteed by applying statistical QC to verify, with a specified probability, that a desired quality requirement is actually achieved in routine laboratory testing. Analytical quality assurance, applied in this way, can be a quantitative approach for guaranteeing quality through process planning and QC.

Health Planning Guidelines↗
PubMed2000

Radiographic quality control devices.

In this study, we evaluate eight radiographic quality control (QC) devices, which noninvasively measure the output from a variety of diagnostic x-ray production systems. When used as part of a quality assurance (QA) program, radiographic QC devices help ensure that x-ray equipment is working within acceptable limits. This in turn helps ensure that high-quality images are achieved with appropriate radiation doses and that resources are used efficiently (for example, by minimizing the number of repeat exposures required). Our testing focused on the physical performance, ease of use, and service and maintenance characteristics that affect the use of these devices for periodic, routine measurements of x-ray system parameters. We found that all the evaluated models satisfactorily measure all the parameters normally needed for a QA program. However, we did identify a number of differences among the models--particularly in the range of exposure levels that can be effectively measured and the ease of use. Three models perform well for a variety of applications and are very easy to use; we rate them Preferred. Three additional models have minor limitations but otherwise perform well; we rate them Acceptable. We recommend against purchasing two models because, although each performs acceptably for most applications, neither model can measure low levels of radiation. This Evaluation covers devices designed to measure the output of x-ray tubes noninvasively. These devices, called radiographic quality control (QC) devices, or QC meters, are typically used by medical physicists, x-ray engineers, biomedical engineers, and suitably trained radiographic technologists to make QC measurements. We focus on the use of these devices as part of an overall quality assurance (QA) program. We have not evaluated their use for other applications, such as acceptance testing. To be included in this study, a device must be able to measure the exposure- and kVp-related characteristics of most x-ray systems. At minimum, it must be able to make routine QC measurements of general radiographic, fluoroscopic, and most mammographic equipment. We prefer that it also be usable with dental x-ray systems, more advanced mammography systems (see the supplementary article on page 103), and computed tomography (CT) systems. The device may be a single unit, or it may be a kit consisting of multiple components that, when combined, can perform all the relevant measurements. The evaluated devices are designed to assess only x-ray production systems, not x-ray detection systems such as image intensifiers and film. Those types of systems are typically assessed using test phantoms and other tools that produce test images, which can be quantitatively measured and compared against standards.

Equipment Design↗
PubMedDate not supplied

Quality control tests for vaccines in leprosy vaccine trial, Avadi.

All the vaccines supplied for the large scale comparative leprosy vaccine trial of ICRC bacilli, M.w, BCG plus killed M. leprae (candidate vaccines), BCG and normal saline (control arms) at CJIL Field Unit, Chennai were tested for quality control by the suppliers following the procedures laid down in the WHO protocol for killed M. leprae. Quality control for BCG was carried out at BCG vaccine laboratory as per protocol. Toxicity and sterility tests were done on all the vaccine batches/lots received. As part of the quality control, bacterial count, and protein estimation were also done. Studies showed that the bacterial content and protein concentration were comparable with the original preparations. Vaccines were free from micro-organisms, toxic materials and safe for human use. Thus the quality of all vaccine preparations was satisfactory.

BCG Vaccine↗
PubMed1995

A quality control system for the optimized sperm penetration assay.

OBJECTIVE: To develop a quality control system for the optimized sperm penetration assay (SPA) and to use this system to monitor interassay variability and stability over time. DESIGN: Four semen donors were tested consecutively for a period of weeks (7 to 139 weeks) with the SPA. Their average semen analyses and SPA scores were evaluated to monitor natural biologic variation. Intra-assay variation was obtained by dividing 11 semen samples into three aliquots and testing each separately in the SPA. A single ejaculate from seven individuals was aliquoted and frozen to be used as a control. They were tested on different assay days in 1986 and subsequently in 1991 to evaluate the assay stability over time. MAIN OUTCOME MEASURES: Results were expressed as a sperm capacitation index (mean number of sperm penetrations per ovum). RESULTS: Consecutive weekly semen analyses and SPAs on donors exhibited coefficients of variation ranging from 20% to > 40%. In contrast, these variations were much greater than intra-assay variability. Analysis of frozen semen specimens tested in several SPAs also displayed a low coefficient of variation. When aliquots of these frozen samples were tested in the SPA 5 years later, there were no differences in the observed values, showing the remarkable stability of this assay over time. The lower limit of the normal fertile range did not change over a period of 2 years. CONCLUSIONS: Results show that using fresh semen samples as a positive control in the SPA is inadequate. This deficiency has been overcome with the use of frozen semen controls. With frozen semen for quality control, the optimized SPA developed in this laboratory is a highly reproducible assay that meets the strict criteria required for clinical laboratory certification.

Animals↗
PubMed2002

[Progress in the replacement of animal experiments in the quality control of clostridial vaccines].

Animal experiments still play a central role in the quality control of vaccines. Generally, performance of these experiments is provided by law and laid down in the European Pharmacopoeia. Classical vaccines, the efficacy of which is calculated in International Units, require a very high number of experimental animals for quality control testing. The testing mainly consists of infection and intoxication experiments causing extreme suffering of the animals involved. This classical product group includes clostridial vaccines which are used to a great extent in veterinary medicine in particular. Within the last years, considerable efforts have been made to reduce the number of animal experiments in this field, lower the number of animals, and decrease the suffering of the animals during testing. Several research projects for the development and validation of alternative methods have been initiated. Furthermore, the 3R Concept (Replacement, Reduction and Refinement) is increasingly taken into consideration when developing or revising legal provisions. This led to various improvements regarding animal welfare in the quality control of clostridial vaccines.

Animal Testing Alternatives↗
PubMed2005

Some practical thoughts on restructuring the current guideline of the Federal Medical Council (Richtlinie der Bundesärztekammer [RiliBAK]) in Germany for quality control of clinical laboratory analyses based on results from external quality assessment surveys.

The present article presents a critical review of the current guidelines of the Federal Medical Council (Richtlinie der Bundesärztekammer--[RiliBAK]) in Germany, both for internal and external quality control. Examples have been chosen for analytes which present problems. These include thyrotropin (TSH) and human chorionic gonadotropin (hCG). Data are presented for the difference in analyte concentrations found between methods/kits and longitudinally for external quality assessment (EQA-) surveys for analytes using reference method values as target values. These include: calcium, aspartate aminotransferase (ASAT; GOT), aldosterone, cortisol, 17beta-oestradiol and total thyroxine (TT4). Furthermore, internal data from participating laboratories concerning laboratory internal precision and accuracy have been analysed to show the state of the art with regard to both parameters. Data analysis shows the need for a reintroduction of concentration-dependent assessment of performance (crossover system) for certain analytes, where clinically relevant concentrations are measured at the extremes of the calibration curve. The current guideline is at present being restructured and should include considerations made in this review of the state-of-the-art of clinical laboratory analysis.

Clinical Laboratory Techniques↗
PubMed1999

Establishing a quality control program for an automated dosimetry system.

Automatic dosimetry systems can provide instantaneous dose and dose-rate information during fluoroscopic procedures as well as long-term records of patient doses. For this information to be useful, it is necessary that the accuracy of such systems be maintained through a rigorous quality control program. Daily and weekly quality control checks were performed on a PEMNET automated dosimetry system to determine its stability and the value of such tests in a quality control program. Weekly tests included monitoring the accuracy of the measured doses under a variety of conditions. The results of the tests indicate possible improvements in test methodology and real and potential sources of system failure and provide a statistical basis for setting quality control limits for future system monitoring.

Biophysical Phenomena↗
PubMed2001

Single-photon emission computed tomography in the year 2001: instrumentation and quality control.

OBJECTIVE: SPECT instrumentation is more complex than that used for whole-body and planar imaging, and requires careful quality control to ensure optimum performance. Conventional and new hybrid SPECT imaging systems (coincidence and SPECT/CT) will be discussed. New imaging detector materials such as LSO and CZT will also be discussed, along with their potential advantages. Finally, basic SPECT quality control will be reviewed. After reading this article, the nuclear medicine technologist should be able to: (a) explain the use of single and multihead gamma cameras for SPECT imaging; (b) have an understanding of the potential of new hybrid SPECT imaging systems; (c) be aware of future developments in SPECT imaging technology; (d) understand the requirements for SPECT quality control, including field uniformity and center of rotation corrections; and (e) explain the benefits of using phantoms to augment SPECT quality control.

Gamma Cameras↗
PubMed1993

The relevance and use of mouse embryo bioassays for quality control in an assisted reproductive technology program.

OBJECTIVE: To define both the limits of a mouse embryo bioassay for quality control in an assisted reproductive technology (ART) program and the areas where it can be effectively used. DESIGN: Embryos at the pronuclear and two-cell stage from three different strains of mice were used to assess the effectiveness of this assay for media quality control using five different media routinely used in ART. Pronuclear and two-cell embryos from CD-1 mice were used to test the ability of a mouse embryo bioassay to control for water quality, contaminants in the culture system, and fluctuations in the environmental conditions using a medium, culture system, and scoring technique that were optimized for this strain. RESULTS: The mouse embryo bioassay is not effective in differentiating media appropriate for supporting human embryo development since the development of mouse embryos in vitro is strain, stage, and media related. However, CD-1 embryos were shown to be sensitive to variations in water quality, pH, temperature, incubator conditions, and contaminants in the system when grown in a protein-free medium optimized for their development. Both total blastocyst number and the cell count in the blastocysts were affected. Pronuclear embryos were more sensitive to perturbations in the culture system than two-cell embryos. CONCLUSIONS: A mouse embryo bioassay can be effectively used as a means of quality control of water, chemicals, and contact materials and for technique standardization and training in an assisted reproduction program. All the conditions of the test should be defined, pronuclear embryos should be used, and the end point should be fully expanded blastocysts and/or cell numbers in these blastocysts where appropriate.

Animals↗
PubMed1988

Time series modeling for quality control in clinical chemistry.

Autocorrelation of clinical chemistry quality-control (Q/C) measurements causes one of the basic assumptions underlying the use of Levey-Jennings control charts to be violated and performance to be degraded. This is the requirement that the observations be statistically independent. We present a proposal for a new approach to statistical quality control that removes this difficulty. We propose to replace the current single control chart of raw Q/C data with two charts: (a) a common cause chart, representing a Box-Jenkins ARIMA time-series model of any underlying persisting nonrandomness in the process, and (b) a special cause chart of the residuals from the above model, which, being free of such persisting nonrandomness, fulfills the criteria for use of the standard Levey-Jennings plotting format and standard control rules. We provide a comparison of the performance of our proposed approach with that of current practice.

Chemistry, Clinical↗
PubMed1999

Quality control validation in veterinary laboratories.

Quality control (QC) validation is used to determine: 1) whether statistical QC procedures are appropriate for detecting medically important errors; and 2) the equality of performance required by different laboratory tests. QC validation is well documented in the medical literature, but we are unaware of studies addressing its application, problems or unique differences in veterinary laboratories. We applied QC validation to automated hematology and biochemistry analyses in our laboratories, with goals of >/= 90% probability of error detection and </= 5% probability of false rejection. Analytical quality requirements in the form of total allowable error were defined using regulatory criteria for human proficiency testing; these were later modified based on clinician and pathologist feedback. Initial QC goals were not met for 14 of 49 (28.6%) analyte-control combinations. Subsequent modifications in methodology, analytical quality requirements and technician training achieved QC goals for all but one analyte. For this analyte (platelet count, low control), nonstatistical QC procedures were emphasized. QC validation was beneficial for clarifying statistical QC performance, and for assessing the need and justification for changes in methods and personnel training. The validation exercise allowed simplification of QC rules, enabled machine flagging of abnormal results, and decreased time and expense associated with QC recording, analysis, problem-solving and reruns. QC validation is recommended for all veterinary laboratories as a useful tool in total quality management.

Journal Article↗
PubMed2005

Protein quality control in Alzheimer's disease: a fatal saviour.

Aggregation of Abeta plays a key role in the pathogenesis of Alzheimer's disease. Although the highly structured Abeta aggregates (fibrils) have long been thought to be the toxic form of Abeta, recent evidence suggests that smaller, soluble intermediates in Abeta aggregation are the real culprit. Because these oligomeric aggregates are already formed in the secretory pathway, this raises another issue: Is intra- or extracellular Abeta involved in the pathogenic cascade? Because aggregated proteins are very toxic, cells have developed quality control responses to deal with such proteins. A prime site for quality culum. Here, aberrant proteins are recognized and can be targeted for degradation to the cytosolic quality control system. In addition, there is accumulating evidence for quality control in other subcellular compartments in the cell. All quality control mechanisms are initially protective, but will become destructive after prolonged accumulation of aggregated proteins. This is enhanced by decreased efficiency of these systems during aging and therefore, these responses may play an important role in the pathogenesis of Alzheimer's disease. In this review, we will discuss the role of protein quality control in the neurotoxicity of Abeta.

Alzheimer Disease↗