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PubMed2005

[Study on quality control of effective fraction in qixue bingzhi decoction].

OBJECTIVE: To develop a method for quality control of effective fraction in Qi-Xue-Bing-Zhi decoction, a traditional Chinese medicine (TCM). METHOD: PF samples, effective fraction from Qi-Xue-Bing-Zhi decoction, were used as example, and a HPLC assay for chemical fingerprint and quantitative analysis was established. RESULT: The contents range of Paeoniflorin (PE), Naringin (NG) and Neohesperidin (NH) in effective fractions were changed from 12.5%-16.0%, 8.4%-12.4%, 12.8%-15.3%, and their average contents were (14.7 +/- 1.1)%, (10.6 +/- 1.2)%, (14.2 +/- 0.8)% (n = 10), respectively. The fingerprints of PF samples showed 25 common peaks, and the fingerprint similarity for PF samples were all above 99.00% by comparing with the standard chromatogram. CONCLUSION: The method reported could be used effectively for the quality control of effective fraction from TCM.

Benzoates↗

PubMed1993

[Quality control of health care: epidemiological aspects].

Quality control in health care should be performed by health professionals. To do so they must define indicators, set up studies aimed at measuring and analyzing quality of care, and implement quality assurance programs in health care systems. The elements of a quality improvement program of this kind are described, with special emphasis on the contribution of epidemiology in this field.

Epidemiologic Methods↗

PubMed2005

Validation and quality control of protein microarray-based analytical methods.

The microarray has emerged as an important format for simultaneous analysis of tens of thousands of substances present in a sample. Successful adaptation of microarray assays to clinical diagnostics will require particular attention to issues of quality control and quality assurance. Results of an assay can be compromised by a number of preanalytical factors including the quality of the reagents (e.g., the microarray and the detection reagents) and the integrity of the sample. Similarly, numerous factors in the analytical phase of a microarray assay, including changes in the reaction conditions and calibration, can contribute to inaccuracy and imprecision. Furthermore, a microarray combines many reagents or samples in a single device and therefore presents additional issues not usually encountered in discrete testing of a single analyte in a single sample. Various strategies (e.g., replicate analysis, array orientation control features, on-array controls, normalization) have been implemented to control and assess analytical factors that might compromise data generated from a microarray. The current range of measures taken to ensure the analytical accuracy and quality of data generated from protein microarrays is reviewed in the context of the lessons learned from DNA microarrays. The special considerations for protein microarrays as they transition from research into routine clinical analysis and the resulting quality control of clinical test results generated using such devices are discussed.

Computational Biology↗

PubMed2003

[Quality control during radiation therapy].

The aim of quality control procedures during radiation therapy is to check the consistency between actual and prescribed treatments. Given the technical complexity of modern radiotherapy, stricter policies are necessary to meet increasing requirements for quality and safety. Among the various tools available, electronic imaging systems play an increasing role in patient-beam position checking and in vivo dose measurements. Written procedures will have to be established in order to describe the control modalities and frequency, as well as the rules for error corrections according to the treatment intent. Non medical staff will be devoted to new tasks, under the radiation oncologist's responsibility. A special attention should be directed at electronic archives, since the present technology is unlikely to meet the legal requirement to keep medical records accessible for at least 30 years.

Diagnostic Imaging↗

PubMed1991

Proposed interpretive criteria and quality control parameters for testing in vitro susceptibility of Neisseria gonorrhoeae to ciprofloxacin.

Ciprofloxacin was subjected to a multilaboratory study designed to determine its in vitro susceptibility criteria for Neisseria gonorrhoeae and its quality control parameters for both agar dilution and disk diffusion susceptibility testing for this species. All clinical isolates were susceptible, i.e., MICs were less than or equal to 0.06 microgram/ml and zones of inhibition were greater than or equal to 36 mm. A resistant category could not be defined, but in vitro-selected mutants gave zones of less than or equal to 35 mm, and MICs for these strains were greater than or equal to 0.12 microgram/ml. For quality control of ciprofloxacin agar dilution tests on supplemented GC agar, MICs for Staphylococcus aureus ATCC 29213 ranged from 0.12 to 0.5 microgram/ml. For quality control of 5-micrograms ciprofloxacin disk tests, N. gonorrhoeae ATCC 49226 and S. aureus ATCC 25923 produced acceptable zone diameter ranges of 48 to 58 mm and 22 to 26 mm, respectively.

Ciprofloxacin↗

PubMed1993

Intra- and interlaboratory quality control for assay of amino acids in biological fluids: 14 years of the French experience.

The functioning of an external quality-control scheme for amino acids set up in 1978 is described. Two measurements were made each month by participating laboratories on a control plasma sample provided by the quality-control center; freeze-dried samples were used from 1978 to 1989 and liquid samples since 1990. In addition, two "blind" samples were sent to the laboratories each year. Every 3 months, the overall results and those of the individual laboratories were analyzed statistically. The validity of the liquid sample control is demonstrated. The progressive improvement of results is commendable. In 1990, the coefficients of variation for all participants ranged from 8.4% for alanine to 23.5% for methionine. The standards used for calibration could contribute to the broad range of results, especially those for histidine and ornithine. The use of blind samples made it possible to detect problems of calibration, of linearity of measurement, of contamination, and of identification of unusual amino acids.

Amino Acids↗

PubMed1979

Influence of a between-run component of variation, choice of control limits, and shape of error distribution on the performance characteristics of rules for internal quality control.

A computer-stimulation study has been performed to determine how the performance characteristics of quality-control rules are affected by the presence of a between-run component of variation, the choice of control limits (calculated from within-run vs. total standard deviations), and the shape of the error distribution. When a between-run standard deviation (Sb) exists and control limits are calculated from the total standard deviation (St, which includes Sb as well as the within-run standard deviation, Sw), there is generally a loss in ability to detect analytical disturbances or errors. With control limits calculated from Sw, there is generally an increase in the level of false rejections. The presence of non-gaussian error distribution appears to have considerably less effect. It can be recommended that random error be controlled by use of a chi-square or range-control rule, with control limits calculated from Sw. Optimal control of systematic errors is difficult when Sb exists. An effort should be made to reduce Sb, and this will lead to increased ability to detect analytical errors. When Sb is tolerated or accepted as part of the baseline state of operation for the analytical method, then further increases in the number of control observations will be necessary to achieve a given probability for error detection.

Chemistry, Clinical↗

PubMed2001

Quantitative quality control in microarray image processing and data acquisition.

A new integrated image analysis package with quantitative quality control schemes is described for cDNA microarray technology. The package employs an iterative algorithm that utilizes both intensity characteristics and spatial information of the spots on a microarray image for signal-background segmentation and defines five quality scores for each spot to record irregularities in spot intensity, size and background noise levels. A composite score q(com) is defined based on these individual scores to give an overall assessment of spot quality. Using q(com) we demonstrate that the inherent variability in intensity ratio measurements is closely correlated with spot quality, namely spots with higher quality give less variable measurements and vice versa. In addition, gauging data by q(com) can improve data reliability dramatically and efficiently. We further show that the variability in ratio measurements drops exponentially with increasing q(com) and, for the majority of spots at the high quality end, this improvement is mainly due to an improvement in correlation between the two dyes. Based on these studies, we discuss the potential of quantitative quality control for microarray data and the possibility of filtering and normalizing microarray data using a quality metrics-dependent scheme.

Algorithms↗

PubMed1989

Evaluation of two types of 'medically significant error limits' and two quality control procedures on a multichannel analyzer.

Analytical error limits based on two different concepts of "medical significance" are derived. The ability of the system to detect medically significant errors using standard (1(3s] and enhanced (mean and range) quality control procedures is investigated. Error detection is found to be adequate for most analytes when error limits are based on physicians' opinions and a mean and range quality control system is used. Error detection is unsatisfactory when error limits based on intraindividual biological variation are used and this cannot be improved by using better quality control systems. The limiting factor is analytical precision. The use of error limits based on biological variation as proposed by major clinical chemistry professional bodies cannot be achieved using most current types of analytical technology.

Biochemistry↗

PubMed2005

A novel method for creating artificial mutant samples for performance evaluation and quality control in clinical molecular genetics.

The lack of readily available, patient-derived materials for molecular genetic testing of many heterozygous or rare disorders creates a major impediment for laboratory proficiency and quality control procedures. The paucity of clinically derived mutation-positive samples could be surmounted if it were possible to construct artificial samples containing mutations of interest that would sufficiently resemble natural human samples. Such samples could then function as acceptable and realistic performance evaluation challenges and quality control reagents for recipient laboratories. Using the cystic fibrosis gene (CFTR) as a prototype, we have devised and executed experiments designed to generate unique DNA samples that could be used for these purposes. We used site-directed mutagenesis to generate mutations of interest in plasmid DNA derived from common bacterial artificial chromosome sources containing the cystic fibrosis transmembrane conductance receptor gene. CFTR mutations G85E and 1078delT were chosen to represent mutations in the original American College of Medical Genetics-recommended population-screening panel of 25 mutations. DNA samples containing predetermined concentrations and ratios of wild-type and mutated plasmids, bacterial artificial chromosomes of interest, and nonhuman genomic carrier DNA were characterized and tested in-house and in a group of nine pilot testing laboratories using a variety of technical platforms. The results indicate that these constructs, containing CFTR mutations in heterozygous and homozygous states, can serve as valid and accessible materials for quality assurance, including performance evaluation, proficiency testing, and assay quality control.

Cystic Fibrosis Transmembrane Conductance Regulato↗

PubMed2004

[Quality control of clinical-grade recombinant adenovirus used in gene therapy].

OBJECTIVE: To establish the quality control methods and reference standards for clinical-grade recombinant adenovirus products for human gene therapy. METHODS: The Infectivity of clinical grade recombinant adenoviral vectors is determined by a TCID(50) assay. The purity is determined by a high-performance liquid chromatography (HPLC) assay. A549 cells were used in replication competent adenovirus (RCA) assay of samples by observation of the cytopathic effect. Other quality control assays were performed in accordance with the SFDA Regulations for Biological Products. RESULTS: The recombinant adenovirus encoding human p53 gene produced at SiBiono (Lot 20010701) has the following quality attributes: viral particle concentration: 1.03 (10(12) VP/ml, infectivity titer: 5.01 (10(10) IU/ml, specific infectivity (IU/VP): 4.86%, higher than the 3.3% required by the Food and Drug Administration (FDA), USA; Purity by HPLC analysis: 98.62%, higher than the 95% purity specified by SFDA; and level of RCA: less than 1 RCA/3 (10(10) VP, meeting the standards established by SFDA. CONCLUSIONS: A whole set of quality standards of clinical-grade recombinant adenovirus vectors has been established so as to ensure the clinical safety and efficacy of recombinant adenoviral vectors for human gene therapy.

Adenoviridae↗

PubMed1995

Quality control in a peritoneal dialysis program.

A reliable and effective quality-control program in the peritoneal dialysis (PD) unit requires a team effort. Historically, the nursing staff has been responsible for PD program development, and in some programs the physicians are frankly uninvolved. An enthusiastic, knowledgeable, and committed physician is necessary. In the early days of continuous ambulatory peritoneal dialysis in the United States, lack of physician understanding and commitment tarnished the image of this promising, evolving therapy. After recognizing this problem, Baxter embarked on an intensive effort to upgrade the expertise of the physicians. Concurrently, PD programs were identified with successful outcomes and "best demonstrated practice" techniques were promulgated. The key to quality control is the involvement of all members of the team, including physicians, nurses, dietitians, social workers, technicians, administrators, and patients. A commitment is needed for continuing education, continuing reevaluation of policies and procedures, and the empowerment of all team members to achieve the programmatic goals.

Education, Medical, Continuing↗

PubMed2000

Quality control in multicentric clinical trials. An experience of the EORTC Gynecological Cancer Cooperative Group.

Data Quality is a central requirement of scientific research and external monitoring is essential in multicentric clinical trials (MCT). A quality control (QC) study was conducted in the main Institutions participating in EORTC-GCCG Protocol number 55863 - randomised phase III trial of vindesine, cisplatin, bleomycin and mitomycin-C (BEMP) versus cisplatin (P) in disseminated squamous cell carcinoma of the uterine cervix - in order to assess the impact of variations in data quality on the conclusions of the trial. The reliability of the different centres in following the protocol was investigated by a questionnaire covering drug prescription, local facilities and the procedure for preparation and administration of chemotherapy. The 'treatment protocol adherence' was evaluated by recalculation of the ideal protocol dose and its comparison with the actual delivered dosage at each cycle of chemotherapy. 'Data quality control' was assessed by comparison of data on case report forms (CRFs) with the corresponding items in the medical records. Eleven centres participating in the trial were visited by the same team of reviewers. Striking differences were noted in the chemotherapy administration procedures and between the type and quality of hospital files. Overall, there was an acceptable level of data quality and protocol compliance. Data accuracy was 81.8% (range: 65. 6-97%) of the 4424 items checked. Incorrect data were found in 7.0% (2.3-14.5%), data were missing on the form in 3.6% of cases (0-12%) and data was on the form but not in the file in 7.6% of cases (0. 7-17.5%). Causes of inaccuracy were analysed. Both problems in data management but also in a lack of clarity of the protocol and/or CRFs were to blame. Training and supervision of data managers, precision in writing protocols, standardisation of some aspects of CRFs and the use of a checklist for chemotherapy data and treatment toxicities would have avoided many of these errors. The need for QC in all collaborative groups performing MCT is emphasised. A literature review on QC in MCT dealing with chemotherapy is included.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

Acquiring proficiency in off-pump surgery: traversing the learning curve, reproducibility, and quality control.

As the risk profile of patients considered for surgical revascularization worsens, the cumulative benefit of off-pump coronary artery bypass (OPCAB) over conventional coronary artery bypass grafting, in terms of lower morbidity and reduced healthcare costs, may increase. There is still resistance to the introduction of OPCAB surgery however, its practice is variable and surgical residents are rarely trained in these techniques. This article considers how the learning curve in OPCAB may be negotiated and prospectively monitored to ensure quality control. The evidence suggests that situations in which suitable senior expertise exists, OPCAB surgery can be introduced into surgical practice and safely taught to trainees without detriment to patients. This is achieved by a progressive increase in the complexity of the case mix and careful early supervision. The introduction of OPCAB has coincided with the increasing use of control charts as quality control tools. Performance monitoring provides reassurance that patients are not being put at risk during the introduction of OPCAB; control chart methods can be used prospectively for real time performance monitoring by consultant surgeons and residents alike. These techniques may ultimately be used to determine proficiency and accreditation. Increasing use of parallel training techniques, the development of structured training programs that encompass OPCAB and other new technologies in cardiac surgery, coupled with objective performance monitoring are warranted to meet the needs of a changing patient population.

Clinical Competence↗

PubMed1979

Quality control of radioimmunoassays for proteins: the first two and a half years of a national scheme for serum growth hormone measurements.

The philosophy and achievements of the first two and a half years of a national quality control scheme for serum growth hormone assays are described. Three serum samples were distributed to participating laboratories every two weeks. A computer-produced summary of the quality control results, which contained scattergrams and a statistical analysis, was returned to participants four weeks after despatch. The performance of 11 experienced (SAS) laboratories was found to fulfil the necessary accuracy criteria, and their results provided the 'reference group mean', which served as the target value. Gross positive bias exhibited by several laboratories was due to the use of assays with inadequate sensitivity, and this practice was eliminated during the first six months. During the course of the Scheme the average bias fell from 30 to 14%. With assays of adequate sensitivity, bias was almost invariably due to the misuse of standards. Median within-laboratory, between-batch precision (CV) improved from 23 to 15%. The best performers achieved between-batch CV of 7% which was 1.5 x their within-batch CV: the worst had three- to four-fold differences between within- and between-batch CV. Rudimentary quality control of interpretation was found to result in improvements in interpretation per se and also served to reinforce the desire to improve numerical agreement. A 'recommended procedure' based upon supplied first and second antibody, and a communal 'reference range' from 280 untreated acromegalics, both proved valuable.

Growth Hormone↗

PubMed1996

Quality control guidelines for amoxicillin, amoxicillin-clavulanate, azithromycin, piperacillin-tazobactam, roxithromycin, ticarcillin, ticarcillin-clavulanate, trovafloxacin (CP 99,219), U-100592, and U-100766 for various National Committee for Clinical Laboratory Standards susceptibility testing methods. Results from multicenter trials.

Quality control guidelines for standardized antimicrobial susceptibility test methods are critical to the continuing accuracy of the tests. In this report, quality control limits were proposed for 22 organism-antimicrobial combinations with minimum inhibitory concentration (MIC) ranges of three or four log2 dilution steps. Disk diffusion zone diameter ranges were proposed for azithromycin compared with Neisseria gonorrhoeae ATCC 49226 and ticarcillin with and without clavulanic acid tested against Staphylococcus aureus ATCC 25923. The data from five or six participating laboratories produced > or = 94.7% of results within proposed MIC limits, and 94.3%-99.0% of zones were found within suggested zone guidelines. These proposed quality control ranges should be validated by in-use results from clinical laboratories.

Acetamides↗

PubMed1969

Quality control in haematology: report of interlaboratory trials in Britain.

An interlaboratory quality control scheme has been established in Britain by the British Committee for Standards in Haematology. In the first instance this has been confined to haemoglobin, red blood cell count, and packed cell volume. The materials which have been circulated include whole blood, stabilized red cell preparations, lysates, cyanmethaemoglobin solutions, and cyanmethaemoglobin reference preparations. The first two trials have been completed, and there are implications for instrument calibration, dilution techniques, and the use of standards. Periodic interlaboratory trials, at a national level, in conjunction with regular individual intralaboratory quality control procedures, are necessary in order to achieve acceptable levels of accuracy and precision.

Clinical Laboratory Techniques↗

PubMed1981

[Quality control during mammography-II (author's transl)].

The results of a pilot study on mammographic quality control in 58 x-ray departments in West Berlin are reported. Using a systematically developed phantom, an insight was gained into the present state of mammography and various unexpected faults which were diagnostically important, were revealed. Standard values for the type of radiation, effective image contrast, resolution, geometry and radiation dose could be ascertained, which can serve as a basis for mammographic quality control.

Berlin↗