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PubMed1998

[Appropriate laboratory use of microbiological testing for quality control and nosocomial infection control].

Useful information from clinical microbiological tests is required for clinical diagnosis and treatment of infectious disease, whereas concern about the quality of information is still low. To provide reliable information in clinical microbiological testing, it is necessary to control the quality of clinical specimens, because of its random character. Through effective use of laboratory testing database, it will be possible to shift away our vague management of pre-analytic phase of quality control so far to its established system based on objective evaluation. During the past 4 years, after the introduction of microbiological tests and information system in our hospital, the characteristics of sputum have become worse contrary to our expectations. This suggests that quality control needs successive improvements, even in service departments such as clinical laboratories. Application of laboratory testing database to nosocomial infection control is considered to be a performance of post-analytic phase of quality control from the viewpoint of effective use of laboratory data. We presented in this paper our practical application of the database to the short-term and long-term control of nosocomial infection.

Clinical Laboratory Information Systems↗
PubMed2005

HTS quality control and data analysis: a process to maximize information from a high-throughput screen.

Changes in all aspects of HTS from compound management through to evaluation of hits and leads, strengthened by infrastructure improvements, in both automation and informatics, have made possible increased analysis and implementation of process and quality control throughout HTS. This paper focuses on the process of HTS with an emphasis on quality control, reducing the variability of all the processes that have an impact on the final result, and argue that by increasing the quality of the entire process that data mining of primary screening data is in fact possible and will reduce cycle times to medicinal chemistry.

Automation↗
PubMedDate not supplied

Two quality control procedures on radiotherapy beam calibration and treatment planning system implementation.

New challenging dosimetric approaches, such as narrow beams and 3D algorithms, are being used in radiotherapy. In this paper two quality control (QC) procedures are reported. The first one concerns the QC of the dosimetry of small x-ray beams, generally carried out by using silicon detectors. The comparison of dose values obtained by a silicon diode, a diamond detector, and radiochromic films shows that for x-ray beams of high energy, the silicon diode can give an overestimation of the output factors in phantom, up to 4%. This is due to the higher than unit density silicon diode and the surrounding envelope that restore the lateral electron equilibrium. About the 3D algorithms for breast treatment planning, a quality control test has been adopted to verify the accuracy of the computed dosimetry when "loss of scatter" occurs. The results show a sensible agreement (within 1.5%) between computed and experimental data.

Humans↗
PubMed1976

Some observations on the quality control testing of Clostridium chauvoei vaccines.

Agglutination tests are not suitable for the estimation of the protective antibody level in the sera of vaccinated animals and should not be used for the quality control testing of blackleg vaccines. Some highly virulent strains of Cl. chauvoei are only effectively protected against by vaccines containing cells with a heat labile protective antigen in addition to the heat stable antigen common to all cells of Cl. chauvoei. As these highly virulent strains may be encountered in the field it is important that such strains should be selected for the challenge of vaccinated animals in the quality control testing of blackleg vaccines. It would be useful if an international center could be responsible for the collection and distribution of such strains.

Agglutination Tests↗
PubMed1976

A method for the statistical evaluation of results in external quality control surveys.

A method for the evaluation of results in external quality control surveys is developed on purely statistical grounds. This system allows to establish accuracy and precision of assay methods by comparing statistical data from subsequent surveys. However, for a particular survey the overall accuracy, precision and quality of each laboratory are defined in statistical terms and visually displayed. Results for each laboratory are summarized on a two-page computer printout. Per component assayed and combining all components determined in the particular survey, the laboratory is assigned one of the four possible qualifications i.e. "very good", "moderate" or "bad". A few general conclusions drawn from experimental data of previous surveys are reported.

Blood Glucose↗
PubMed2004

Utility of bag segment and cryovial samples for quality control and confirmatory HLA typing in umbilical cord blood banking.

Many cord blood (CB) banks have been established worldwide as a response to the increasing number of CB transplantations. In this study, we describe a quality control program in which the utility of an integral bag segment and cryovial containing aliquots of cryopreserved product as haematopoietic content control and HLA typing confirmation for CB units has been evaluated. For this purpose, every month one stored CB unit and its satellite cryovials were thawed and washed. Nucleated cell counts, viability and clonogenic assays were performed from the bag and cryovial before washing. After washing, total nucleated cell, CD34+ counts, viability, and clonogenic assays were performed from the bag. In order to assure the ability of bag segments to confirm hematopoietic potential of CB units, clonogenic assays and viability were performed from attached segments of 10 CB units and the results were compared with those from bags and cryovials. When comparing all variables between thawed bag and cryovial samples, they showed similar results. Mean colony-forming unit (CFU) content of segment samples was 118.8 +/- 93.72 x 10(4) that resulted similar to bags and cryovials haematopoietic content. In conclusion, the quality control system described in this paper demonstrates that CB units are processed preserving the quantity and quality of the progenitor cells. The contiguous segment haematopoietic content is representative of the final product.

Blood Banks↗
PubMed2006

The exponentially weighted moving average (EWMA) rule compared with traditionally used quality control rules.

BACKGROUND: The exponentially moving average (EWMA) rule for internal quality control is a well-known type of control rule in industry. Here, the power of the EWMA rule is evaluated to outline the potential of this type of control rule in clinical chemistry. METHODS: Using simulations, the power of the EWMA rule was explicitly compared with that of commonly used rules in clinical chemistry. The type I error levels were standardized to common values to achieve unbiased comparisons. RESULTS: For small to moderately large errors (systematic errors up to 2-3 standard deviations), the EWMA rule outperforms simple rules (N=1) and multi-rules (N=2-6). For example, for a systematic error of 2s, the EWMA rule equivalent to the 1(3s) rule has a power of 0.30, whereas the 1(3s) rule only displays a power of approximately 0.15. For N=4, comparison was carried out with the 1(3s)/2(2s)/R(4s)/4(1s) rule. Here the common type I error level is 0.017. At all error levels, the EWMA rule is superior to the multi-rule. For example, given a 1s systematic error, the EWMA rule has a power (0.4) of twice the value of the multi-rule (0.2). CONCLUSION: The EWMA rule is an efficient control rule with regard to systematic errors that should be considered for general application in the field of clinical chemistry.

Chemistry, Clinical↗
PubMed1998

[Cervical screening--its essence and quality-control methodology in cytology laboratories].

The essence and importance of the quality control in the activity of the cytological laboratories, fulfilling the 1st step of the cervical screening are discussed. The methodology is presented, as well as the possibilities of the different kinds of internal and external control and the place of the introduced in the practice of the developed countries automated analyzing systems are under consideration.

Cytological Techniques↗
PubMed2003

[Quality control plan for a primary bladder neoplastic process].

OBJECTIVES: Delays in the diagnosis and treatment of bladder cancer may change survival rates (6). We present the application of a plan for quality control in the management of primary bladder cancer, studying delays globally, and for individual indicators, as well as the impact of implemented improvement measures. METHODS: We performed a retrospective chart review to detect problems appeared through the whole clinical management process in a population of patients undergoing surgery for primary bladder cancer in the Hospital Costa del Sol during 2001. Causes were studied and corrective measures established, application of which has been evaluated during the first semester of 2002. Study indicators encompass from delay time for first visit to delay time for radical surgical treatment. RESULTS: Excessive average global delays for radical treatment of bladder tumor (208.3 days), and variability in the time to transurethral resection (one to 73.42 days) and to postoperative revision (54.4 days), were the most significant results. Evaluation of implemented measures shows a descent in global delays (134.2 days) and time to postoperative revision variability (32.4 days). CONCLUSIONS: Application of quality control procedures for clinical management is essential in daily clinical practice, for systematic, continuous, and rigorous evaluation will allow us to offer patients a product that satisfies their personal and social expectations.

Case Management↗
PubMed2001

The role of chaperone-assisted folding and quality control in inborn errors of metabolism: protein folding disorders.

Molecular chaperones are present in the various compartments of the cell and assist the folding of newly synthesized proteins. Compared to wild-type proteins, missense mutant proteins are generally synthesized in a normal fashion, but may be impaired in their folding. A broad array of diseases that are due to misfolding of mutant proteins may be labelled conformational diseases: aggregation diseases, such as Alzheimer disease; diseases caused by negative dominance from misfolded structural proteins, such as hypertrophic cardiomyopathy; and disorders where the misfolded protein is degraded by intracellular proteases. Many metabolic disorders belong to this last category, where the so-called protein quality control systems, comprising chaperones and proteases, attempt to eliminate folding intermediates or misfolded proteins. On the basis of in vitro experiments with a limited number of missense mutations identified in patients with phenylalanine hydroxylase and fatty acid oxidation deficiencies, we discuss the cellular fate of missense mutant proteins. We find that the balance between folding to functional conformers, retention (holding) and degradation of folding intermediates or misfolded proteins is dependent on the nature of the mutation and on the efficiency of the quality control. For example, low temperature may promote formation of functional conformers, while elevated temperature usually promotes retention and degradation. We conclude that disorders caused by many missense mutations are complex diseases in which the mutation itself is a necessary major primary component, but that its effect may be modified by cellular conditions and possibly by genetic variations in the quality control systems. We suggest that this new knowledge about cell handling may open new avenues of understanding of the cell pathology and treatment of patients with metabolic disorders.

Animals↗
PubMed1988

Ceftibuten (7432-S, SCH 39720): comparative antimicrobial activity against 4735 clinical isolates, beta-lactamase stability and broth microdilution quality control guidelines.

The antimicrobial activity of ceftibuten, a new oral cephalosporin, was evaluated using 4735 clinical bacterial isolates processed at four medical centers. Ceftibuten inhibited nearly 92% of all Enterobacteriaceae (less than or equal to 8.0 micrograms/ml), thereby being markedly superior to cefixime which inhibited 78.7% at less than or equal to 1.0 microgram/ml and cefuroxime which inhibited 45.1% at less than or equal to 2.0 micrograms/ml. Pseudomonads and staphylococci were not within the spectrum of activity of ceftibuten. Ceftibuten was found to be very stable in the presence of five commonly occurring beta-lactamases of both the chromosomal-mediated (P99, K1) and plasmid-mediated (CARB-2, OXA-1, TEM-1) types. Only Type Ia (P99) beta-lactamase was significantly inhibited by ceftibuten. On the basis of results of a ceftibuten MIC quality control study conducted in five laboratories, a quality control range of 0.12 to 0.5 microgram/ml is recommended for the Escherichia coli ATCC 25922 strain.

Anti-Bacterial Agents↗
PubMed2005

Quality control in neutrophil granulocyte (PMN) concentrates by flow cytometry.

BACKGROUND: In peripheral blood, chemotaxis, phagocytosis, and oxidative burst of polymorphonuclear cells (PMNs) can be assessed by flow cytometry, whereas function tests, i.e., quality control in PMN concentrates designed for neutropenia therapy, are lacking. METHODS: PMN concentrates (n=6) harvested from healthy donors who had been premedicated with granulocyte colony-stimulating factor (G-CSF) and dexamethasone were stored undiluted (control, C; n=6) and diluted 1:4 (D; n=6) with autologous plasma for 72 h. Commercial flow cytometry function tests were performed to quantify changes in chemotaxis, phagocytosis, and oxidative burst of PMNs over time. RESULTS: Median levels of phagocytosis and oxidative burst levelled at 86% (82-94) and 98% (83-100) in C on the day of apheresis, respectively, but deteriorated to 15% (0-24) and 0% within 72 h; in D these parameters remained close to 90%. Median levels of chemotaxis were comparable in C (69%, 65-74) and D (74%, 70-84) at baseline. No migration was detected in C after 72 h; however, D retained approximately 63% (13-76) migration capacity. CONCLUSION: Quality control in PMN concentrates is practical using flow cytometry and commercial test kits. While phagocytosis and oxidative burst may be maintained for 72 h in vitro, chemotaxis of apheresed PMNs is already reduced on the day of apheresis.

Chemotaxis, Leukocyte↗
PubMed2002

Quality control of mechanical ventilation at the patient's home.

OBJECTIVE: During home mechanical ventilation the prescribed settings are applied without permanent supervision of health professionals. After a long-time period of unattended operation at home the ventilator may not apply the ventilation parameters prescribed. This quality control study of home mechanical ventilation assessed whether tidal volume (V(T)), frequency (f), and minute ventilation (V'(E)) actually applied by the ventilator coincide with the values set on the ventilator control panel and with those prescribed. MEASUREMENTS: Actual V(T), f, and V'(E) applied by the ventilator in 30 patients on nocturnal HMV were measured at the patients' homes. The patients were subjected to volume targeted assist ventilation through nasal mask (n=28) or tracheostomy (n=2). The values of V(T), f, and V'(E) set at the ventilator were recorded. The actual and set V(T), f, and V'(E) values were compared with those prescribed. RESULTS: Considerable differences were found between actual, set and prescribed V(T), f, and V'(E). Actual V'(E) was significantly lower than V'(E) set: mean difference was 0.82 l/min, with considerable individual differences. Differences between actual and prescribed V'(E) were caused both by a poor performance of the ventilator and by a discrepancy between the values prescribed and those set at the ventilator control panel. CONCLUSIONS: Regularly assessing the actual performance of ventilators at the patient's home is a quality control procedure useful for detecting malfunctions which could improve compliance and outcome of home mechanical ventilation.

Adult↗
PubMed1981

[Clarification of anemia: quality control in the general practice laboratory].

In mailed blood samples from 602 adult patients with beta-thalassaemia trait, a mean MCH value of 20.5 pg with a 2 s range of 17-24 pg was found. These values are identical to those determined in fresh blood samples. Furthermore, the Gaussian distribution indicates that reliable values are obtained in mailed blood samples. From patients with previous blood analyses in hospital and biochemical laboratories the MCH values of the foreign laboratories correlated well with our results (r = 0.87). On the other hand, a poor correlation was observed for private practice laboratories (r = 0.71). The difference of the two correlation coefficients is statistically highly significant (p less than 0.001). There is clearly a need for MCH quality control in the laboratories of many practitioners. Continuous quality control by means of values from healthy persons and the use of stabilized control blood is recommended.

Erythrocyte Count↗
PubMed1993

Monitoring intensive care unit performance using statistical quality control charts.

This paper discusses results of a study in which mortality rates and APACHE II severity of illness scores of Intensive Care Unit (ICU) patients were monitored for a five-year period (1986-1990) using statistical quality control charts. The purpose of the study was to determine whether severity of illness of patients and mortality rates had changed significantly over this time horizon. The results show that the Intensive Care Unit process is stable and in statistical control. There is no apparent trend in the severity of illness scores nor mortality rates measured both at ten days and six months from the last ICU admission. Quality control charts, which have been used extensively to detect changes in industrial processes on a short term basis, provide a simple method of monitoring the ICU process over an extended time horizon.

Critical Care↗
PubMed1998

An evaluation of quality control activity for near patient testing in primary care.

Near patient activity is now increasing within the United Kingdom and can be a valuable activity within primary care, but only within the confines of safe practice that incorporates quality control procedures. This study identified widespread use of near patient testing (NPT) within primary care but that there is a haphazard approach to specific test performance. Results showed a poor understanding of quality control issues and provide a clear indication of future training and educational priorities if NPT is to develop in primary care.

Diagnostic Tests, Routine↗
PubMed2006

Global quality control perspective for the physical and technical aspects of screen-film mammography--image quality and radiation dose.

The systematic monitoring of image quality and radiation dose is an ultimate solution to ensuring the continuously high quality of mammography examination. At present several protocols exist around the world, and different test objects are used for quality control (QC) of the physical and technical aspects of screen-film mammography. This situation may lead to differences in radiation image quality and dose reported. This article reviews the global QC perspective for the physical and technical aspects of screen-film mammography with regard to image quality and radiation dose. It points out issues that must be resolved in terms of radiation dose and that also affect the comparison.

Body Burden↗
PubMed1990

Performance goals for internal quality control of multichannel haematology analysers.

Performance goals for analytic bias and analytic imprecision are presented for multichannel haematology analysers. These goals represent a compromise between limits that would cause minimal degradation in the information content for clinical decisions and limits that are achievable by current instruments. For midrange measurements the maximal limits for total analytic bias are +/- 14.6% for WBC, +/- 5.3% for RBC, +/- 4.5% for Hb concentration, +/- 4.2% for MCV, and +/- 22% for platelet counts. The limits include error inherent in calibrator value assignment, instrument calibration, instrument drift, and instrument non-linearity as well as the quality control systems necessary to monitor each of these processes. If analytic biases are held within the proposed limits, the clinical specificities of the assays will be decreased by less than 7% for all assays except that platelet counts will have a decrease in specificity of about 15%. Analytic imprecision has minimal direct effect on clinical decisions because the influence of within-person and across-person biological variation dominates. However, analytic imprecision is a major factor in the control of analytic bias and thereby remains an important quality control factor.

Blood Cell Count↗