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PubMed1997

Components of the costs of controlling quality: a transaction cost economics approach.

This article identifies the components that contribute to a healthcare organization's costs in controlling quality. A central tenet of our argument is that at its core, quality is the result of a series of transactions among members of a diverse network. Transaction cost economics is applied internally to analyze intraorganizational transactions that contribute to quality control, and questions for future research are posed.

Cost Allocation↗

PubMed2003

Reliability of nucleic acid amplification methods for detection of Chlamydia trachomatis in urine: results of the first international collaborative quality control study among 96 laboratories.

The first European Quality Control Concerted Action study was organized to assess the ability of laboratories to detect Chlamydia trachomatis in a panel of urine samples by nucleic acid amplification tests (NATs). The panel consisted of lyophilized urine samples, including three negative, two strongly positive, and five weakly positive samples. Ninety-six laboratories in 22 countries participated with a total of 102 data sets. Of 204 strongly positive samples 199 (97.5%) were correctly reported, and of 506 weakly positive samples 466 (92.1%) were correctly reported. In 74 (72.5%) data sets correct results were reported on all samples, and 17 data sets (16.7%) showed either one false-negative or one false-positive result. In another 11 data sets, two or more incorrect results were reported, and two data sets reported a false-positive result on one negative sample. The Roche COBAS Amplicor test was performed in 44 (43%) data sets, the Abbott LCx assay was performed in 31 (30%) data sets, the Roche Amplicor manual assay was performed in 9 (9%) data sets, an in-house PCR was performed in 9 (9%) data sets, the Becton Dickinson ProbeTec ET assay was performed in 5 (4.9%) data sets, and the GenProbe TMA assay was performed in 4 (3.9%) data sets. The results of the Roche Amplicor manual (95.6% correct), COBAS Amplicor (97.0%), and Abbott LCx (94.8%) tests were comparable (P = 0.48). The results with the in-house PCR, BD ProbeTec ET, and GenProbe TMA tests were reported correctly in 88.6, 98, and 92.5% of the tests, respectively. Freeze-drying of clinical urine specimens proved to be a successful method for generating standardized, stable, and easy-to-transport samples for the detection of C. trachomatis by using NATs. Although the results, especially the specificity, for this proficiency panel were better than most quality control studies, sensitivity problems occurred frequently, underlining the need for good laboratory practice and reference reagents to monitor the performance of these assays.

Chlamydia Infections↗

PubMed2003

Metadata element set in a quality-controlled subject gateway: a step to a health semantic Web.

BACKGROUND: Quality-controlled subject gateways are Internet services which apply a selected set of targeted measures to support systematic resource discovery. Considerable manual effort is used to process a selection of resources which meet quality criteria and to display a extensive description and indexing of these resources with standards-based metadata. OBJECTIVE: Several metadata element sets are proposed to describe, index and quality health resources to be included in a French quality-controlled health gateway called CISMeF. The main objectives were to enhance Internet health document retrieval and navigation, and to allow interoperability with other Internet services. RESULTS: The Dublin Core metadata element set is used to describe and index all Internet health resources included in CISMeF. For teaching resources, some elements from IEEE1484 Learning Object Metadata are also used. For evidenced-base medicine resources, specific metadata are employed which assess the health content quality. The HIDDEL metadata set is used to enhance transparency, trust and quality of health information on the Internet. CONCLUSION: Comprehensive metadata element sets can be extremely useful to describe, index and assess health resources on the Internet in a quality-controlled subject gateway. Machine-readable metadata creates an Semantic Web which is more efficient for end-users as compared to the current Web.

Abstracting and Indexing↗

PubMed1978

Internal quality control of radioimmunoassays.

A modified cumulative sum technique has been applied to radioimmunoassay quality control data. The method is approximately 50% more efficient in detecting systematic changes in the mean and variance of quality control values for plasma samples than more widely used conventional methods. The salient features of the technique have been restricted to changes in the mean quality control value of a plasma pool, but potential applications to changes in variance and as a diagnostic aid to problems in radioimmunoassay have been evaluated. The method is independent of computing facilities and statistical expertise since all computations have been presented in the form of a nomogram and thus can be used by technicians at the bench.

Estradiol↗

PubMed2001

Major histocompatibility class I folding, assembly, and degradation: a paradigm for two-stage quality control in the endoplasmic reticulum.

Protein folding in living cells is a complex process involving many interdependent factors. The primary site for folding of nascent proteins destined for secretion is the endoplasmic reticulum (ER). Several disease states, including cystic fibrosis, are brought about because of irregularities in protein folding. Under normal cellular conditions, "quality control" mechanisms ensure that only correctly folded proteins are exported from the ER, with incorrectly folded or incompletely assembled proteins being degraded. Quality control mechanisms can be divided into two broad processes: (1) Primary quality control involves general mechanisms that are not specific for individual proteins; these monitor the fidelity of nascent protein folding in the ER and mediate the destruction of incompletely folded proteins. (2) Partially folded or assembled proteins may be subject to secondary quality control mechanisms that are protein- or protein-family-specific. Here we use the folding and assembly of major histocompatibility complex (MHC) class I as an example to illustrate the processes of quality control in the ER. MHC class I, a trimeric complex assembled in the ER of virally infected or malignant cells, presents antigenic peptide to cytotoxic T lymphocytes; this mediates cell killing and thereby prevents the spread of infection or malignancy. The folding and assembly of MHC class I is subjected to both primary and secondary quality control mechanisms that lead either to correct folding, assembly, and secretion or to degradation via a proteasome-associated mechanism.

Animals↗

PubMed1999

[External quality control in the Federal Health Survey: concept and site visits].

The results of the German National Health Interview and Examination Survey will be of great importance for health policy and research. Therefore, internal quality management was supplemented by an external quality control which was carried out by a private company (Bernhard Schwertner Feld organisation, Augsburg). The interviewer training, sampling and response, field work and data management were included into the external quality control. For each of these four areas, measures of control and detailed check-lists were provided by the external quality control. The aim was to find sources of potential and real errors and to arrive at recommendations for internal quality management. The general concept of external quality control is briefly presented and experiences and results from the quality control of the field work are described in the present paper.

Adolescent↗

PubMed1998

Centralized echocardiogram quality control in a multicenter study of regression of left ventricular hypertrophy in hypertension.

OBJECTIVE: To test the feasibility and utility of instituting centralized echocardiographic quality control during a multicenter study of regression of left ventricular hypertrophy in hypertension. DESIGN AND METHODS: The LIVE (Left Ventricular Hypertrophy: Indapamide Versus Enalapril) study is an ongoing multicenter, double-blind, controlled study of regression of echocardiographic left ventricular mass index in hypertensive patients with left ventricular hypertrophy (left ventricular mass indexes > 100 g/m2 for women and > 120 g/m2 for men) treated for 1 year with 1.5 mg indapamide sustained-release coated tablets versus 20 mg enalapril. A centralized evaluation committee has validated a prestudy sample echocardiogram from each center, and is now reviewing all videotapes recorded during this study for quality control; final results will be based on a further randomized blinded analysis by this centralized evaluation committee. RESULTS: Since December 1994, 878 patients have been preselected (videoechocardiographic recordings sent for assessment), 645 selected (videoechocardiographic recordings validated), and 576 randomly allocated to treatment. After preliminary quality control, 27% (233) of baseline echocardiograms were rejected by our centralized evaluation committee, and 22% (142) of postinclusion echocardiographic measurements had to be repeated, mainly because they were of poor echogenic quality. Analysis of approved baseline echocardiograms for the first 274 randomly allocated patients with digitized data showed that there was a significant correlation between centralized evaluation committee and investigator calculations of left ventricular mass index (r = 0.76, P < 0.001), with consistently higher values for investigator calculations, independently of level of left ventricular mass index (correlation between difference and mean of investigator and centralized evaluation committee measurements, r = 0.08, P = 0.28). The mean difference was 8 +/- 20 g/m2 (P < 0.001). CONCLUSION: Early results of the LIVE study quality control showed that real-time 'live', centralized echocardiographic reading was not only feasible, but also useful for avoiding unquantifiable echocardiograms and overestimation of left ventricular mass index. Thus, real-time, centralized echocardiographic quality control should be recommended for multicenter studies of regression of left ventricular hypertrophy.

Adult↗

PubMed2001

In vivo action of the HRD ubiquitin ligase complex: mechanisms of endoplasmic reticulum quality control and sterol regulation.

Ubiquitination is used to target both normal proteins for specific regulated degradation and misfolded proteins for purposes of quality control destruction. Ubiquitin ligases, or E3 proteins, promote ubiquitination by effecting the specific transfer of ubiquitin from the correct ubiquitin-conjugating enzyme, or E2 protein, to the target substrate. Substrate specificity is usually determined by specific sequence determinants, or degrons, in the target substrate that are recognized by the ubiquitin ligase. In quality control, however, a potentially vast collection of proteins with characteristic hallmarks of misfolding or misassembly are targeted with high specificity despite the lack of any sequence similarity between substrates. In order to understand the mechanisms of quality control ubiquitination, we have focused our attention on the first characterized quality control ubiquitin ligase, the HRD complex, which is responsible for the endoplasmic reticulum (ER)-associated degradation (ERAD) of numerous ER-resident proteins. Using an in vivo cross-linking assay, we directly examined the association of the separate HRD complex components with various ERAD substrates. We have discovered that the HRD ubiquitin ligase complex associates with both ERAD substrates and stable proteins, but only mediates ubiquitin-conjugating enzyme association with ERAD substrates. Our studies with the sterol pathway-regulated ERAD substrate Hmg2p, an isozyme of the yeast cholesterol biosynthetic enzyme HMG-coenzyme A reductase (HMGR), indicated that the HRD complex discerns between a degradation-competent "misfolded" state and a stable, tightly folded state. Thus, it appears that the physiologically regulated, HRD-dependent degradation of HMGR is effected by a programmed structural transition from a stable protein to a quality control substrate.

Animals↗

PubMed2001

Quality control within the Asthma Clinical Research Network.

Quality control and assurance are very important issues for multicenter clinical investigation. Although such investigation usually states that those factors are part of the investigation, at best this occurs to a minimal extent. Indeed, to ensure the best possible investigatory results with the least amount of variance between centers, the Asthma Clinical Research Network (ACRN) instituted strict written criteria that were continually overviewed. This article describes the ACRN's quality control of: clinic procedures and equipment, training and certification of study personnel, site visit evaluations, and the procedures of bronchoscopy and sputum induction. The examples given in this report demonstrate how various aspects of our investigation are performed.

Asthma↗

PubMed1999

[Quality control of reactant lots at the Nation Blood Group Reference Center (CNRGS). Data for the year 1998].

The reagents used for blood group analyses are subject in France to the same regulations as other reagents. A file must be submitted for each reagent to the Agence française de sécurité sanitaire des produits de santé. Furthermore, each production lot must be checked by the Centre national de référence pour les groupes sanguins (CNRGS) for control before marketing. These controls allow a comparative quality assessment of the reagents. The investigation by the CNRGS of the problems encountered in the every day use of these products makes this quality control even more accurate.

Blood Banks↗

PubMedDate not supplied

Rapid rescreening of cervical smears for internal quality control.

OBJECTIVE: To assess the performance of quick rescreening as an internal quality control for cervical smears previously screened as negative and to compare this method with clinically indicated rescreening of negative smears and with further 10% random rescreening. STUDY DESIGN: In a small-workload laboratory with many different types of indications for cytology, during a three-month period, all gynecologic cytology smears considered negative for significant findings (anything above atypical squamous cells of undetermined significance (ASCUS)/atypical glandular cells of undetermined significance (AGUS) in the Bethesda System) or inadequate were quickly rescreened using a 10 x objective. RESULTS: Of the total 2,188 smears processed, 164 (7.5%) were excluded from rapid review because they were positive on routine screening, and 2,024 cases were subjected to rapid rescreening: 1,925 (95.1%) cases were considered negative and 99 (4.9%) positive for significant findings; 58 of the latter were confirmed and 41 not confirmed by the cytopathologist's detailed examination. The 58 confirmed cases were classified as: 43 ASCUS/AGUS, 14 of low grade squamous intraepithelial lesion and 1 of invasive cancer. No cases of high grade squamous intraepithelial lesion were detected. CONCLUSION: Considering that the routine screening and internal quality control of the laboratory had detected 117 positive cases, the additional 58 represent a definite increase in the efficiency of a small-workload laboratory. In such a clinical setting, no additional case of a high grade lesion was detected by rapid rescreening. The increase in cost and time was considered very reasonable, and the method was incorporated as quality control for the laboratory. Clinically indicated rescreening of negative smears and random 10% rescreening after random rescreening did not add significantly to quality assurance.

Carcinoma, Squamous Cell↗

PubMed1997

A technique for standardization and quality control of subjective sperm motility assessments in semen analysis.

OBJECTIVE: To establish a quality control method to monitor and eventually to standardize the subjective assessment of sperm motility in conventional semen analysis. DESIGN: Quality control study running over 2 years. SETTING: University infertility clinic and andrology laboratory. PATIENT(S): Randomly chosen patients attending the clinic. MAIN OUTCOME MEASURE(S): Conventional semen analysis with sperm motility assessed by grading according to the World Health Organization (WHO) criteria and analysis of individual sperm tracks with a computer-aided sperm analysis (CASA) system. Formulas were established to identify, from the track data, the threshold velocity values for distinguishing between motility grades a and b and motility grades b and c for each technician. RESULT(S): The subjective thresholds above which technicians categorized sperm as WHO grades a and b were determined by CASA to be 61 +/- 1 and 11 +/- 1 micron/s (straight-line velocity), respectively. Agreement among three to five technicians over 2 years was reasonable (coefficient of variation < 20%), but threshold values were variable. CONCLUSION(S): Agreement within and between laboratories in the assessment of sperm motility grades could be achieved by agreeing on designated values for threshold velocities for grade a and b sperm. On the basis of such values, CASA analysis could be used to provide the expected percentages of grades a, b, and c forms for quality control samples recorded and distributed on videotapes, against which technicians could adjust their subjective assessments.

Analysis of Variance↗

PubMed2000

[Quality control of laboratory diagnosis of urogenital infectious].

The diagnosis of urogenital infections in practical public health services is not always supported by adequate measures aimed at quality control. Scientists developing new diagnostic methods should pay special attention to improvement of methods for quality control of diagnostic studies in a laboratory. Introduction of methods precluding regular quality control is not advisable. In cases when quality control studies are impossible for objective reasons, a complex of methods should be used in diagnostic studies.

Clinical Laboratory Techniques↗

PubMed2006

Fit-for-purpose shellfish reference materials for internal and external quality control in the analysis of phycotoxins.

The need for reference materials for quality control of analysis of foodstuffs has been stressed frequently. This has been particularly true in the phycotoxins field, where there is a great shortage of both pure calibration standards and reference materials. Worldwide there are very few independent bodies that produce certified reference materials for phycotoxins, the main producers currently being the National Research Council Canada and the Japanese Food Research Laboratory. Limited availability of contaminated shellfish and algae, as well as the time and knowledge necessary for the production of adequate reference materials, continuously lead to limited editions of certified reference materials and even more limited production of in-house reference materials. The restricted availability of in-house quality control materials promotes the rapid use of the limited certified reference materials, which in turn hampers the production of the suite of materials required globally for complete protection of public health. This paper outlines the various options that analysts can pursue in the use of reference materials for internal and external quality control, with a view to optimising the efforts of both reference materials users and reference materials producers. For this purpose, the logical sequence is reviewed from the discovery of a new bioactive compound in shellfish, through initial method development up to regulation for food safety purposes including accepted reference methods. Subsequently, the requirements for and efforts typically spent in the production and characterisation of laboratory reference materials, certified reference materials and other test materials used in inter-laboratory studies or proficiency testing, in the area of marine biotoxins are evaluated. Particular emphasis is put on practical advice for the preparation of in-house reference materials. The intricate link between reference material characterisation and method performance is outlined to give guidance on the appropriate in-house method validation in the rapidly developing field of phycotoxins.

Animals↗

PubMed2005

Nordic immunohistochemical quality control.

The use of immunohistochemistry by pathologists has been steadily, almost logarithmically increasing during the last decade. There is no scientific indication that this trend will reverse or slow down. At the same time, quality control issues have not followed this tempo. In particular, external quality control has been neglected. In 1999, nine Scandinavian laboratories established organization, Nordic Quality Control (NordiQC), to provide external quality control in immunohistochemistry for Denmark, Norway, Sweden, and Finland. This commentary briefly describes the work of this organization.

Humans↗

PubMed1993

[Difficulties and problems in external quality control of immunoassay].

Present status and problems in external quality control of immunoassays were described. Despite the increasing popularity of these methods, there are many difficulties in achieving good analytical performance. Consequently, immunoassay results demonstrate poor interlaboratory comparability. To exclude these difficulties, several changes should be made, for example, preparation of common reference standards, consent methods to give values to laboratory working standards, reference methods, matrix of test samples similar to actual clinical samples etc, before constructing suitable external quality control systems.

Humans↗

PubMed1995

Using quality-control analysis of peak expiratory flow recordings to guide therapy for asthma.

OBJECTIVE: To compare the action points in published asthma management plans with those derived from quality-control analysis of peak expiratory flow recordings. DESIGN: Longitudinal observational study. SETTING: An ambulatory asthma education and management program in a tertiary care hospital. PATIENTS: 35 adults with asthma and exacerbation of asthma. MEASUREMENTS: Peak expiratory flow diaries and symptom recordings. RESULTS: Asthma action points from published asthma management guidelines had poor operating characteristics. The success rate was 35% when the action point was a peak expiratory flow rate less than 60% of the patient's best peak flow. The success rate improved to 88% when the action point was a peak expiratory flow rate less than 80% of the patient's best peak flow. Published action points had a high failure rate. Peak flow decreased to below the published action points during a stable period of asthma in 7% to 51% of patients studied. Action points defined using quality-control analysis did significantly better. A peak flow value less than 3 standard deviations below the patient's mean peak flow detected 84% of exacerbations and had a low failure rate (19%). Other quality-control tests had sensitivities of 91% and 71%. Quality-control action points could detect exacerbations up to 4.5 days earlier than conventional methods. CONCLUSIONS: Individualized action points can be derived for patients with asthma by applying quality-control analysis to peak flow recordings. These action points are more sensitive in detecting exacerbations of asthma and have fewer false-positive results. Action plans developed in this manner should be more useful for the early detection of deteriorating asthma.

Adrenal Cortex Hormones↗

PubMedDate not supplied

Mouse tumour tests for quality control of C. parvum preparations.

Description of two mouse tumor tests selected to control the quality of C. parvum pilot productions: transplanted Ehrlich's ascitic tumor in inbred Swiss mice and transplanted YC8 ascitic tumor in isogenic Balb/c mice. The results obtained during three years of control are analyzed, particularly accuracy, long range adequacy and reproducibility of tumor challenges and C, parvum stimulations. The effects of some parameters of the tumor tests, e.g. dose-responses, treatment schedules, tumor-host relationships and standard preparations are discussed.

Animals↗