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PubMed1992

Topical corticosteroids: quality control considerations.

A simple procedure is developed, which can be used as a quality control test. The method utilizes commercially available diffusion cell assembly, synthetic membrane, and an appropriate receptor phase. The amount of drug released over time is determined using an HPLC method. From this, the drug release rate, flux, microgram/cm2/min0.5 is calculated. This drug release rate can serve as a good quality control test to assure batch-to-batch uniformity.

Administration, Topical↗

PubMedDate not supplied

Q-Pro: a quality control management system for medical equipment.

Q-Pro is an application for quality control (QC) and inspection of medical equipment. The system has been designed on the basis of a broad requirements analysis, contributed by clinical engineers from several European countries and with a focus on current and forthcoming regulatory requirements concerning the quality control and risk management for medical equipment. Q-Pro comprises a generalized application, providing the necessary flexibility to accommodate the different degrees of difficulty and specialization in creating or customizing QC protocols, carrying out inspections and managing collected data. The system incorporates a tool library for QC protocol design, widely used multimedia as well as a local database for protocol and inventory data archiving. The paper presents a detailed account of the system context of use, design and functionality.

Equipment and Supplies↗

PubMed1991

Central laboratory sampling plans and quality control in clinical trials.

Central laboratories play an important role in many clinical trials. An important tool in aiding the interpretation of these data has been the use of quality control procedures, primarily achieved by having the central laboratory gather additional data from a subset of the trial participants and therefore obtain a measure of the central laboratory's precision. However, both the additional burden on patients as well as rising clinical trial costs demand that when this trial component is required, it be executed as efficiently as possible. The following analysis explores the relationship between both the number of individuals taking part in the quality assessment and the number of repeated intrapatient measurements on the efficiency of the quality control. This examination reveals that the efficiency of the quality control mechanism for central laboratories is dependent on the sampling scheme used to obtain the specimens, and, in general, a small confidence interval for the variance of reproducibility can be obtained when more than two intrapatient measurements are utilized. Confidence interval lengths are provided for several different combinations of interpatient and intrapatient measurements.

Clinical Trials as Topic↗

PubMed1994

Analytical quality control in neonatal screening.

This critical review questions the present understanding in monitoring of analytical quality control in neonatal screening. Current status and historical background of the analytical quality control, particularly of the tests intended for the screening of congenital hypothyroidism and some inborn errors of metabolism, is reviewed. The reasons why attempts to standardize immunoassays through the preparation of a so-called "gold standard" (e.g. for thyrotropin) will not resolve noncomparability of results are discussed. The review presents arguments for the necessity of elaboration of international guidelines for methods assessment and comparison with an emphasis on their clinical relevance.

Guidelines as Topic↗

PubMed1979

Quality control of drug assays.

Most routine drug assay work is done by clinical chemists who, in general, are well aware of the importance of regular quality control checks. Few, however, have had extensive experience in analytical techniques for drugs, such as gas chromatography, and often underrate the difficulty in obtaining reliable results. Although antiepileptic drugs are among the easiest to measure, a North American study organized by Dr Charles Pippenger and a European study performed by the author demonstrated clearly the poor quality of results coming from many laboratories. From these studies have grown two external quality control schemes which together involve over 800 laboratories on a world-wide basis. Reports have indicated that the reliability of theophylline, tricyclic antidepressant and phenothiazine assays is also poor, and it might be expected that the problems will increase as attempts are made to measure drugs present in lower concentrations. Careful attention to quality control will be essential if physicians are to be provided with reliable results.

Anticonvulsants↗

PubMed1976

[External quality control measures for blood lead analysis of persons living in a high lead exposure area (author's transl)].

Analytical laboratories engaged in studies regarding the exposure of larger population groups to lead should--for the sake of better intercomparability of data--subject themselves to internal and external quality control. In this paper an example of external quality control for blood lead, ALA-D and FEP analysis by 3 institutes is given. Evaluation by correlation analysis showed satisfactory results for all 3 parameters studied. Apart from discussing the results, suggestions are made regarding conduction of realistic quality control measures for the 3 lead-dependent biological exposure parameters.

Adult↗

PubMed1993

[Storage of thrombocyte concentrates: quality control by in vitro bleeding test].

BACKGROUND: The increasing demand for single-donor platelet concentrates necessitates the storage of these blood products prior to transfusion. Quality control of these platelets, however, is still a problem. Most of the available techniques are time-consuming and require sophisticated equipment and specifically trained personnel. The present paper describes a new method for quality control of stored platelet concentrates. MATERIALS AND METHODS: Single-donor platelet concentrates were stored for 7 days; daily aliquots were taken and the in vitro bleeding time (Thrombostat 4000) and platelet aggregation (aggregometer) were determined. RESULTS: The in vitro bleeding test can be handled simply and fast. The results are comparable with those of platelet aggregation tests. CONCLUSION: The in vitro bleeding test provides a good alternative to the conventional methods commonly used for quality control of platelet concentrates.

Bleeding Time↗

PubMed1991

Ability of National Committee for Clinical Laboratory Standards-recommended quality control strains from the American Type Culture Collection to detect errors in disk diffusion susceptibility tests.

The National Committee for Clinical Laboratory Standards (NCCLS) recommends, as a quality control for the disk diffusion susceptibility test, the use of three strains from the American Type Culture Collection: Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 25922. This study assesses the capacity of these strains to detect errors in the overall method. ATCC strains were tested by comparing testing by the standard NCCLS-recommended procedure (ST) with testing under the following conditions: incubation at 25 degrees C, Mueller-Hinton agar depths of 2 mm (AD2) and 8 mm (AD8), agar pHs of 6.5 and 8, inocula with McFarland standards of 0.25 (0.25M) and 4.0 McFarland (4.0M), direct inoculation without preincubation of inoculum (DI), and a 2-h delay between inoculation and disk application (2HR). The frequency of zone measurements outside the NCCLS-recommended control zone limits were as follows: ST, 0%; AD2, 18%; AD8, 9.6%; pH 6.5, 7.9%; pH 8, 5.3%; 0.25M, 3.5%; 4.0M, 24%; DI, 3.4%; 2HR, 1.8%; 25 degrees C (only E. coli and P. aeruginosa were evaluable), 28%. These results suggest that the quality control strains are only partially effective in detecting single extreme laboratory errors and that careful laboratory supervision is necessary even in the setting of properly monitored quality control strains.

Clinical Laboratory Techniques↗

PubMed1984

Evaluation of the quality variations of ejaculates from individual donors for establishing a quality control scheme.

Semen for use in artificial insemination must be of good quality. To satisfy this demand we have to be able to predict the quality of semen from individual donors. Statistical analyses of data on 3,418 ejaculates from 87 donors demonstrated that each donor's ejaculates could be characterized by a lognormal distribution of the sperm concentration, the concentration of motile spermatozoa before freezing and the concentration of motile spermatozoa after thawing. Furthermore, the ratio of the concentration of motile spermatozoa before freezing to the total sperm concentration and the fraction of motile spermatozoa surviving the freezing procedure were found to be constant for individual donors. Based on these observations a statistical quality control scheme for the selection of donors and for the continuous control of semen quality is presented.

Ejaculation↗

PubMed2002

Proposed evaluation of laboratory performance in an external hematology quality control scheme.

The commercial control material for hematology Cell Dyn 16 Tri Level gave a good precision an accuracy using the four blood cell counters currently mostly used in Indonesia, the Coulter, Sysmex, Serono and Cell Dyn. It could be used as one of the hematology control material in an external quality control scheme. Result of the CV from participating laboratories are higher compared to this trial are caused by different level of laboratory technical ability although the geographical area and climate may also play a role. The new scoring calculation to evaluate the participant's performance gave a more wider range of DI scores, to give better insight to the performance of each laboratory.

Hematologic Tests↗

PubMed1994

Development of interpretive criteria and quality control limits for broth microdilution and disk diffusion antimicrobial susceptibility testing of Streptococcus pneumoniae.

A five-center collaborative study was undertaken to develop quality control and specific interpretive criteria for susceptibility testing of Streptococcus pneumoniae against 12 antimicrobial agents. MICs were determined for 248 pneumococcal clinical isolates (with an emphasis on resistant strains) by use of the National Committee for Clinical Laboratory Standards (NCCLS)-recommended broth microdilution procedure incorporating lysed horse blood-supplemented Mueller-Hinton broth. NCCLS disk diffusion testing was also performed for each isolate by using Mueller-Hinton sheep blood agar incubated in 5% CO2. Repetitive testing of S. pneumoniae ATCC 49619 with different sources and lots of media and disks allowed development of quality control ranges which encompassed approximately 95% of MIC and zone size values observed in the study. Good intra- and interlaboratory reproducibilities were seen with these testing methods and all of the drugs examined. On the basis of the results of this study, MIC interpretive criteria are proposed for 11 agents. Comparisons of MICs and disk diffusion zone sizes allowed disk diffusion zone size interpretive criteria to be proposed for five drugs and confirmed the use of the oxacillin disk test for prediction of penicillin susceptibility among pneumococci. Excessive numbers of minor-category interpretive errors precludes recommendation at this time of the disk diffusion method for testing of pneumococci against five of the drugs. Use of these proposed quality control and interpretive criteria should provide for reproducible test results and allow recognition of recently emerging resistance among pneumococcal clinical isolates.

Diffusion↗

PubMed1998

[Quality control of data produced in biological population surveillance studies on the risk of environmental lead poisoning].

The biological surveys of the general population against the risk of lead intoxication carried out in Italy--in accomplishment both of the EEC directive EEC 77/312 and the Presidential Decree 496/1982--have been always conceived as multicentric activities. Therefore, starting from the first campaign carried out in 1979, strict quality control procedures have been adopted. In brief, each participant laboratory used internal quality control samples and took part in external quality assessment exercises. In addition, ten percent of the blood samples collected during the campaign were analyzed as blind duplicate by both participating laboratories and a reference laboratory. In this paper the quality control procedures adopted will be presented and discussed in detail together with the quality of results obtained in each campaign.

Environmental Exposure↗

PubMed2000

Inter-laboratory comparison of flow-volume curve measurements as quality control procedure in the framework of an international epidemiological study (PEACE project).

The aim of this work was to describe the results of a simple quality control procedure for the flow-volume curve adopted in a multicentre epidemiological study (PEACE). In 14 centres, 8-15 individuals (n = 157) performed forced vital capacity (FVC) manoeuvres following a standard protocol with both the local spirometer/pneumotachograph and a portable spirometer (i.e. the 'reference instrument' for this study). Deviances of measurements were assessed by computing the differences (delta) between the former and the latter, the ratios of such differences on portable spirometer values (delta %) and the coefficients of variation (CV). The portable spirometer yielded lower mean AFVC and deltaFEV1 (forced in 1 sec) than local instruments (except for two and four centres, respectively). In most instances, differences were statistically significant. Absolute mean A%FVC ranged from 4.9-18.2%, while delta%FEV1 ranged from 2.3-18.5%. The Bland and Altman analysis showed a good agreement between the portable and local instruments, except for two centres, where a systematic trend towards higher individual absolute deltaFVC and deltaFEV1 was observed. The overall variability, assessed by CV, was within 6.2% and 5.1% for FVC and FEV1, respectively: it was similar to other quality control studies ranging from 2.0-5.5% for FVC and 2.2-5.8% for FEV1. Our results point out the importance of performing interlaboratory comparisons as a quality control procedure in multicentre epidemiological studies on lung function, and of stimulating manufacturers to extend the accuracy and precision of the instruments.

Adolescent↗

PubMed2005

Quality control of spirometry: a lesson from the BRONCUS trial.

This report describes the quality control programme used within the Bronchitis Randomized on N-acetylcysteine (NAC) Cost-Utility Study, a trial designed to assess the decline in lung function, exacerbation rate, health status, and cost-effectiveness with NAC or a placebo in 523 patients with chronic obstructive pulmonary disease over a 3-yr period. Spirometry was scored from 0 (worst quality) to 6 (best quality). The mean score of 314 spirometries from 243 patients evaluated during the trial was 5.63+/-0.83. Linear regression analysis of the scores of 47 participating centres plotted against the time at which spirometries were performed yielded an intercept of 5.7+/-0.5 and a slope of -0.0001+/-0.001, which suggests that the initial high quality was maintained over time. Retrospective examination of a further 345 postbronchodilator spirometries from 208 patients with a forced expiratory volume at one second exceeding the mean individual value recorded over the study in excess of 20% revealed a slightly lower quality of the start-of-test manoeuvre compared with the 314 spirometries. In conclusion, these findings would suggest that the quality control programme is likely to have helped achieve and maintain long-term spirometry performance in the Bronchitis Randomized on N-acetylcysteine (NAC) Cost-Utility Study trial. Special care should be paid to the spirometries whose forced expiratory volume in one second values exceed the mean value.

Acetylcysteine↗

PubMed1981

Quality control limits for ampicillin, carbenicillin, mezlocillin, and piperacillin disk diffusion susceptibility tests: a collaborative study.

A multilaboratory in vitro study was carried out to determine disk diffusion susceptibility testing quality control limits for two new semisynthetic penicillins, mezlocillin and piperacillin. Existing limits for carbenicillin and ampicillin were reevaluated. Multiple tests (which followed standards set by the National Committee for Clinical Laboratory Standards ASM-2 revised) were performed in nine laboratories by different technologists using disks and Mueller-Hinton agar from different manufacturers. Clinically significant differences between disks produced by different manufacturers were not noted. Inhibitory zone diameter measurements from all laboratories were analyzed, and upper and lower control limits were established by using the overall median +/-0.5 the median range of the individual laboratory measurements as determining parameters. Close agreement of the data in this study with the results of national proficiency testing and quality control programs for ampicillin and carbenicillin supports the validity of our approach to making initial recommendations for quality control guidelines for new antimicrobial agents.

Ampicillin↗

PubMed1996

[Quality control of human albumin solutions].

Human albumin is a major product of the fractionation of human plasma, with a long history of clinical use. While the manufacturing process of human albumin solutions has not undergone significant changes, these products have benefited from progress in pharmaceutical technology, quality control and quality assurance, which enhance their clinical safety. Besides the strict requirements of pharmacopoeia monographs which describe the minimal quality criteria with which products must comply, the quality of the final products relies on a careful in-process control, to guarantee the applicability of validated manufacturing processes and to prevent risks of chemical, bacteriological, viral or endotoxic contamination of the product. The development of new analytical methods for quality control and/or their increasing sensitivity also contributes to the improvement of the quality of these products.

Albumins↗

PubMed1999

Quality control of postoperative acute pain service.

To establish an effective method of continuous quality control of acute pain service, a retrospective study on incident reporting during postoperative analgesia period was conducted. Incidents were reported and analyzed in 1507 patients who received epidural postoperative analgesia, and the results of satisfaction of pain relief was compared with those of incident analysis. In this study, an incident was defined as any factor that might or had affected patient's safety during analgesia period. Our results showed that 1203 incidents were reported in 641 of 1507 patients, of which 122 incidents were critical. 78.3% of all incidents were detected by acute pain service stuff. The most common incidents included complications, insufficient analgesia and problems with delivery circuits. Human factors were involved in 28.9% of the incidents, most being associated with technical failure due to unskillfulness, poor communications between APS stuff and patients and lack of cooperation with surgeons and nurses. The general satisfaction rate of the patients was 90.8%. There was a very significant difference between the satisfaction of the patients who suffered from incidents and who did not (P < 0.001). It is concluded that incidents affect the satisfaction of the patients who received postoperative pain relief. Incident reporting is a more effective method for quality control of acute pain service.

Analgesia, Epidural↗

PubMed2005

[Quality control in imaging standards for stroke diagnosis].

Hospitals in "Rhineland-Palatinate" and "Saarland" as well as in other German states are using benchmarking in quality control and to improve diagnostic procedures and treatment in stroke. The goal is a continuous learning process in which participants improve their performance by comparing themselves to the highest quality care. CCT/MRI procedures are an important tool in stroke therapy and prophylaxis. Structural quality was good in all 39 participating hospitals. The best evidence-based indicator in quality control of CCT/MRI procedures is the process quality in performing these procedures within 3 h after stroke onset. Process quality was better in hospitals that cared for many stroke patients than in those with fewer cases. The latter hospitals also had less clinical and diagnostic competence. Benchmarking in quality control was successful because over the years improvement in stroke management was obvious in the participating hospitals.

Appointments and Schedules↗