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PubMed1992

Cost efficient sampling design for quality control of a birth defects registry.

Quality control studies of registries are frequently conducted. We employed a cost effective sampling scheme for assessing the quality of case identification and abstracting in one birth defects registry. The general sampling method was a stratified two-stage design, and the optimal sample size for each stratum was chosen to minimize cost, which was defined as time for data collection. The resulting sample sizes depended on the variability in the number of abstracts between and within data collection facilities, and the amount of time needed to complete each data collection step. The most time effective scheme was to visit several facilities each for a short period of time rather than fewer facilities for a longer period of time. Cost efficient sampling strategies, such as the method used here, can be applied to ensure precision in registry quality control analyses and other public health studies.

Congenital Abnormalities↗

PubMed1976

Standards and quality control: problems and pitfalls.

The proliferation of standards and quality assurance programs is posing a major problem for mental health administrators. The authors review some of these problems and emphasize the differences between cost and quality controls. They propose that quality controls be judged on their ability to improve patient care and suggest that administrators consider the establishment of quality control offices.

Accreditation↗

PubMed1989

[Comparative observations of internal and external quality controls in the districts of Neubrandenburg and Rostock].

A useful combination of results from internal quality control and external quality assessment is possible only if the statistical procedures of both systems involve the same limits to accept control data. These limits are shown. For 45 laboratories expected quality groups QG-T are calculated from results of internal quality control. Quality groups QG-RVL are calculated from results of external quality control assessment. In 30 cases the great difference of QG-T and QG-RVL is supposed to be caused by inaccurate performance of internal quality control.

Germany, East↗

PubMed1999

[Quality control of the "M. Malpighi" Anatomy, Histology, and Pathologic Cytology Section, Oncology Department, University of Bologna, Bellaria Hospital].

The quality control scheme in use at the Department of Anatomic Pathology of the University of Bologna-Bellaria Hospital Since 1993 a quality assurance (QA) scheme has been set up in our Department, modified from the protocol in use at the Department of Pathology of Yale University and published by J. Rosai in his textbook. A QA committee has been appointed and each member is responsible for a specific branch of the total workload; the areas involved are: 1. review of frozen section diagnoses with the final diagnoses 2. randomized review of biopsies (1:25) 3. quality control of cytological cases 4. quality control of specimen adequacy 5. quality control of immunohistochemistry and in situ Hybridization 6. quality control of the cytogenetics laboratory 7. quality control of autopsies All data collected from january 1996 to february 1999 have been reviewed and analyzed in order to provide references for other laboratories and for the purpose of monitoring our laboratory' performance.

Hospitals, University↗

PubMed1979

A quality control program to evaluate accuracy and precision of clinical chemistry determinations.

An external quality control program is described which, apart from documenting the routine performance of clinical chemistry laboratories with respect to accuracy and precision, also indicates the control efficiency of intra-laboratory quality control procedures. Participants are supplied with a large lot of stable control serum to be used in their intra-laboratory quality control program during a prolonged period of time. The statistical analysis of the submitted data consists of an analysis of variance scheme in order to separate systematic from random errors. The systematic laboratory errors are thereafter graded according to a scoring system independent of the standard deviation. The control efficiency of intra-laboratory quality control procedures is derived from a modified version of the measurability and controllability rules of Van der Grinten (1968) Stat. Neerl. 22, 43--63). Application of these rules in clinical chemistry laboratories is a first step towards a dynamic system of process deviation control. Merits of such an approach are discussed. Principles of the analysis of variance technique are dealt with. A graphical procedure to display its results is shown. Testing procedures to justify application of the analysis of variance technique are discussed and several features are illustrated.

Analysis of Variance↗

PubMed1986

Quality control in hematology.

A quality control (QC) protocol for hematology, as for other sections of the laboratory, should encompass both internal and external QC programs. The extent to which a hematology laboratory should be involved depends upon various factors, including availability of facilities, financial resources, range of tests, workload, the number of staff and their levels of training, and the overall organization of the laboratory. To ensure quality patient care, the intralaboratory QC program must include at least the minimal measures of monitoring and control at each step from collection of blood specimens, through the actual processing and analysis, to reporting of the results. The protocol should be written concisely and in simple language; the procedure manual should offer all of the pertinent information along with references; all concerned personnel should be well trained and competent; and adequate facilities and time should be available for the purpose of QC. Continuing education is also an integral part of an effective QC program. Three very important aspects of QC in hematology are calibration of automated instruments, monitoring of accuracy and precision of instruments and procedures, and verifying the reliability of test results. In the absence of a true primary reference/standard for calibration of instruments for the CBC, the most commonly performed hematologic test, the use of commercial calibrators is acceptable. A combination of commercial controls (three levels) and retained or fresh patient blood specimens is recommended for monitoring of accuracy and precision on a long- and short-term basis. Patient red-cell indices moving average data allow continuous monitoring of instrument performance and should be used as an adjunct to other QC approaches to detecting instrument calibration drift. Correlation of results of related parameters and careful review of blood films remain the two most important and widely used approaches to ensure reliability of results obtained from automated hematology instruments. Participation in an external QC program offers the most practical means of monitoring overall work performance in comparison with instrument, method, and/or reagent-based peer group data. A laboratory may choose to participate in one or more national and/or regional QC programs, depending upon the range of tests it performs and the requirements of accreditation and regulatory agencies. Most of the accreditation agencies require participation in programs covering at least all of the routinely or frequently performed tests and, if available, also in those for infrequently performed tests.(ABSTRACT TRUNCATED AT 400 WORDS)

Hematologic Tests↗

PubMed2005

Degradation-mediated protein quality control in the nucleus.

Protein quality control degradation systems rid the cell of aberrant proteins, preventing detrimental effects on normal cellular function. Although such systems have been identified in most subcellular compartments, none have been found in the nucleus. Here, we report the discovery of such a system in Saccharomyces cerevisiae. It is defined by San1p, a ubiquitin-protein ligase that, in conjunction with the ubiquitin-conjugating enzymes Cdc34p and Ubc1p, targets four distinct mutant nuclear proteins for ubiquitination and destruction by the proteasome. San1p has exquisite specificity for aberrant proteins and does not target the wild-type versions of its mutant substrates. San1p is nuclear localized and requires nuclear localization for function. Loss of SAN1 results in a chronic stress response, underscoring its role of protein quality control in the cell. We propose that San1p-mediated degradation acts as the last line of proteolytic defense against the deleterious accumulation of aberrant proteins in the nucleus and that analogous systems exist in other eukaryotes.

Anaphase-Promoting Complex-Cyclosome↗

PubMed2005

Quality control for microarray experiments.

OBJECTIVES: In this paper we give an overview of post-hybridization quality control methods for gene expression chips, including methods for the gene/spot level, the hybridization/chip level and the process level. We present quality control methods that can be applied after hybridization and image analysis, i.e. that use data from the chip experiment itself. Wet lab quality control steps, which should be applied before the probe is measured on a chip, are not discussed. This review is aimed towards statisticians and data analysts. METHODS: We give examples of some of the quality control measures available for spotted cDNA and Affymetrix GeneChips, the most common chip types. As quality control measures are technology and design-dependent, we will stress on methods that have the potential to be applied platform-independently. RESULTS: Quality control should identify poor quality chips or hybridizations, as well as faulty measurements for individual genes/spots. Additionally, high throughput laboratories processing several tens or hundreds of microarrays per week have the need for an appropriate process control to be able to identify changes in the production process as early as possible. CONCLUSION: Microarrays have become a standard research tool for biologists and medical researchers. As a consequence, there is a great need for standardized quality control, as false findings due to problem in data quality can lead to a substantial loss of resources.

DNA Probes↗

PubMed2003

Ubiquitylation as a quality control system for intracellular proteins.

Quality control of intracellular proteins is essential for cellular homeostasis. Molecular chaperones recognize and contribute to the refolding of misfolded or unfolded proteins, whereas the ubiquitin-proteasome system mediates the degradation of such abnormal proteins. Ubiquitin-protein ligases (E3s) determine the substrate specificity for ubiquitylation and have been classified into HECT and RING-finger families. More recently, however, U-box proteins, which contain a domain (the U box) of about 70 amino acids that is conserved from yeast to humans, have been identified as a new type of E3. The prototype U-box protein, yeast Ufd2, was identified as a ubiquitin chain assembly factor (E4) that cooperates with a ubiquitin-activating enzyme (E1), a ubiquitin-conjugating enzyme (E2), and an E3 to catalyze the formation of a ubiquitin chain on artificial substrates. Yeast Ufd2 is functionally implicated in cell survival under stressful conditions. This review addresses recent progress in characterization of the role of E3 enzymes, especially that of U-box proteins, in quality control of intracellular proteins.

Animals↗

PubMed1999

A protocol building software tool for medical device quality control tests.

Q-Pro is an application for Quality Control and Inspection of Medical Devices. General system requirements include friendly and comprehensive graphical environment and proper, quick, easy and intuitive user interface. Functions such as, a tool library for protocol design widely used multimedia, as well as, a support of a local database for protocol and inventory data archiving are provided by the system. In order to serve the different categories of users, involved in Quality Control procedures, the system has been split into three modules of different functionality and complexity, each of which can work as a stand-alone application. The implementation of protocols and use of the software functions, as well as, the user interface itself have been proved by the evaluators to be clear and intuitive. The software seems to adapt easily to different kinds of Quality Control procedures and objectives. Q-Pro effectively supports and enhances the processes to attain a highly tuned, professional, responsive and effective quality control and preventive maintenance procedures for biomedical equipment management.

Data Collection↗

PubMed1995

Internal quality assurance in a clinical virology laboratory. II. Internal quality control.

AIMS: In April 1991 additional quality control procedures were introduced into the virology section of the Clinical Microbiology and Public Health Laboratory, Cambridge. Internal quality control (IQC) samples were gradually included in the serological assays performed in the laboratory and supplemented kit controls and standard sera. METHODS: From April 1991 to December 1993, 2421 IQC procedures were carried out with reference sera. RESULTS: The IQC samples were evaluated according to the Westgard rules. Violations were recorded in 60 of 1808 (3.3%) controls and were highest in the IQC samples of complement fixation tests (25/312 (8%) of controls submitted for complement fixation tests). CONCLUSIONS: The inclusion of IQC samples in the serological assays performed in the laboratory has highlighted batch to batch variation in commercial assays. The setting of acceptable limits for the IQC samples has increased confidence in the validity of assay results.

Complement Fixation Tests↗

PubMed1986

A quality control system and its application to clinical chemistry.

A quality control system is presented that involves the Quality Control Log for documenting data, decisions, and corrective actions. It emphasizes the use of the Calibration Work Record, cusum, and comparison of means to monitor acute and chronic drift and method bias. It introduces clinically useful limits criteria for efficient and cost-effective quality control.

Calibration↗

PubMed2005

Web quality control for lectures: Supercourse and Amazon.com.

Peer review has been at the corner stone of quality control of the biomedical journals in the past 300 years. With the emergency of the Internet, new models of quality control and peer review are emerging. However, such models are poorly investigated. We would argue that the popular system of quality control used in Amazon.com offers a way to ensure continuous quality improvement in the area of research communications on the Internet. Such system is providing an interesting alternative to the traditional peer review approaches used in the biomedical journals and challenges the traditional paradigms of scientific publishing. This idea is being explored in the context of Supercourse, a library of 2,350 prevention lectures, shared for free by faculty members from over 150 countries. Supercourse is successfully utilizing quality control approaches that are similar to Amazon.com model. Clearly, the existing approaches and emerging alternatives for quality control in scientific communications needs to be assessed scientifically. Rapid explosion of internet technologies could be leveraged to produce better, more cost effective systems for quality control in the biomedical publications and across all sciences.

Commerce↗

PubMed1999

Evaluation of a new reagent for preserving fresh blood samples and its potential usefulness for internal quality controls of multichannel hematology analyzers.

We describe a new, easy-to-use reagent, Cyto-Chex (Streck Laboratories, Omaha, Neb), that preserves fresh whole blood in a non-cross-linking, nonformalin manner. Target values assigned to fresh blood were essentially met after preservation and storage of up to 31 days. Respective mean analytic inaccuracies and short-term intra-assay coefficients of variation (n = 30) were as follows: WBCs, 6.7% and 1.99%; RBCs, 0.7% and 0.76%; hemoglobin, -1.8% and 0.79%; hematocrit, -0.3% and 0.75%; mean corpuscular volume, -1.0% and 0.78%; and platelets, 6.9% and 3.12%. Linearity of dilution-sensitive analytes was satisfactory over a wide range of dilutions after preservation of blood samples. Ten independent laboratories using 10 different instruments determined day-to-day interassay imprecision during four 7-day periods after blood preservation. Mean interassay coefficients of variation for participating laboratories were WBC, 1.92%; RBC, 1.00%; hemoglobin, 1.29%; hematocrit, 2.00%; and platelets 3.29%. Cyto-Chex enables long-term monitoring of instrument accuracy and precision with retained blood specimens of healthy persons. Blood from patient cohorts with various hematologic disorders and with a wide range of numeric abnormalities and/or parameter aberrations can be preserved satisfactorily with this reagent. The reanalysis of preserved patient blood samples is an important adjunct to the use of commercial control material in quality control programs of multichannel hematology analyzers.

Blood Preservation↗

PubMed2006

A new quality control model using performance goals based on biological variation in External Quality Assurance Schemes.

A new quality control model using performance goals based on biological variation in External Quality Assurance Schemes (EQAS) is described. The proposed model aims to use assay (analytical) CV(A), bias and total error available from participation in EQAS to describe assay performance using minimum, desirable and optimum quality specifications based on biological variation. The model provides further analysis of EQAS data and should be useful in better management of laboratory quality control, as it provides further information that can facilitate trouble-shooting. Additionally, it can help in evaluating the performance of current and proposed new laboratory methods by applying a unifying system if different EQAS are used to cover a range of analytes.

Biomarkers, Tumor↗

PubMed1985

Pathology quality control in the cooperative clinical cancer trial programs.

Pathology quality control is an essential part of clinical cancer research. However, pathology review for every study may not be practical; therefore, review in most cooperative groups will be performed only for selected protocols. The selection process should include those neoplasms with an expected diagnostic error rate which would affect the outcome of the study. Unfortunately, complete information about the diagnostic error rate for various neoplasms is not available at the present time; however, enough information is available from the pathology review experiences of the last decade to draw some general guidelines. All lymphomas should have pathology quality control review as should rare or difficult-to-diagnose neoplasms. Early cancer is likely to cause diagnostic disagreement, so protocols designed to evaluate various treatment options for such neoplasms should include pathology review. The diagnostic error rate for far-advanced carcinoma, most adenocarcinomas of the gastrointestinal tract and squamous cell carcinomas, is so low that routine pathologic quality control review is not cost-effective, in our opinion. However, pathology review may be pathology research, and in this circumstance, pathology review will be carried out to answer research questions. Whether or not pathology quality control review is needed should be determined at the time of development of each protocol.

Clinical Trials as Topic↗

PubMed1976

Quality control and the community physician in England: an American perspective.

The quality of health care is becoming an issue of increasing public importance in both England and the United States. As the government role in providing health care grows and citizen demands increase, the effective and efficient use of health care resources and their equitable distribution become crucial. Although government responsibilities, particulary for health care, differ in both countries, as do traditions of quality control, cross-national comparisons are nonetheless useful. An examination of the role of the new English community medicine specialist and his potential for quality control may indicate what tools and powers should be introduced into a health planning and quality control system in the United State. The study concludes that at the district level of the National Health Service, where the basic planning, monitoring, and evaluation of services are to take place, the District Community Physician has very limited tools to carry out his quality control function. Although he has formal position in the unified decision-making structure, it is unlikely that he will be able to effect any substantial reallocation of resource without the voluntary support and copperation of the consultants, general practitioners, and other health providers.

Community Medicine↗

PubMed2003

Evaluation of antiretroviral drug measurements by an interlaboratory quality control program.

Since 1999 an ongoing international interlaboratory quality control program has analyzed antiretroviral drugs in plasma. Results of the third round of this program are presented. Quality control samples were prepared by spiking drug-free plasma with varying concentrations of the currently available protease inhibitors and the nonnucleoside reverse transcriptase inhibitors efavirenz and nevirapine. Thirty-three laboratories participated in the program and were requested to analyze the quality control samples. Results were from 30 laboratories. Of all measurements, 82% were performed within 80%-120% accuracy limits. Only 3 laboratories performed all their measurements within these limits, and 12 participants reported at least 90% of their analyses within the acceptance range. Mean accuracy for low drug concentrations was worse than for medium and high concentrations. The percentage of satisfactory measurements for the 6 laboratories that participated for the third time in the program increased from 54% in the first round to 85% in the third round. The program revealed a large variability in the laboratories' ability to measure antiretroviral drugs accurately. This variability may have important implications for therapeutic drug monitoring of these drugs and for pharmacokinetic studies. Interlaboratory testing is useful to alert laboratories to previously undetected analytical problems.

Alkynes↗