Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “quality control”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed1984

A practical statistical quality control scheme for the industrial hygiene chemistry laboratory.

A computerized statistical quality control system has been developed for use in the industrial hygiene chemistry laboratory. The system is practical and sufficiently flexible to allow for multiple analytes, concentrations, replicate sizes and sample types. The computerized system provides an immediate evaluation of the quality of analytical results and produces automatically simple but informative accuracy and precision quality control charts.

Chemistry Techniques, Analytical↗
PubMed2003

[Quality control of plant extract].

The current situation of plant extract in domestic and international market was analyzed in the paper. The quality control of 20 plant extracts which have reasonably good sales in USA market was compared and analyzed. The analysis of the quality control of six plant extracts indicated that there were two main reasons leading to the varied quality specifications among different suppliers. One reason was that the plant species utilized by different companies were different. The other reason was that the extraction processes were different among different production plants. Comparing with the significant international suppliers of plant extracts, the product quality of Chinese companies were not satisfactory. It was suggested that chromatography and chromatographic fingerprint techniques should be applied to improve the quality control standard of plant extract in our country.

Anthocyanins↗
PubMed1996

The need for protein containing quality control materials for blood pH and electrolyte analyzers.

In clinical chemistry quality control refers to monitoring of precision and accuracy of the performance of analytical methods. Calibration solutions and (matrixed) control solutions are used in transferring accuracy between definitive method, reference method and field methods. For this purpose aqueous (protein-free), protein-containing and serum-based types of quality control materials having different matrices are available. Here are presented differences in behaviour between aqueous (protein-free) and protein-containing materials. Potentiometry with an electrochemical cell is an often used field method to determine pH and activity of electrolytes with an Ion-Selective Electrode (ISE). Basically, measured e.m.f.'s of calibrators and sample are translated into the activity of the ionic species of the sample by means of the Nernst equation. Besides the standard e.m.f. (E(zero)) of the electrochemical system, the measured e.m.f. includes the ISE-membrane e.m.f. (EISE) and depends on electrolyte type and its concentration and Eij depends on the composition and geometry of the salt bridge. Both EISE and Eij depend on the sample matrix. Protein-containing samples cause a negative bias on the e.m.f. at the liquid junction and a positive bias at the ISE. When EISE and Eij are compared to the mV span of the reference interval, the effects are large for Ca2+, Na+ and Cl-. Exactly the same effects exist for H+, K+, Li+ and Mg2+ but the inaccuracy is less critical for these ions. It may be concluded that only protein containing controls can detect an error that occurs only with measurements on plasma specimens. In practice this means that calibration is checked with protein-free solutions, but that measurements in plasma are best checked with protein-containing solutions.

Acid-Base Equilibrium↗
PubMed1980

Quality-control statistical interpretation by microcomputer.

A comprehensive summary report of quality-control data is of great value in monitoring the accuracy and precision of the clinical chemistry laboratory. This report allows a retrospective appraisal alerting laboratory personnel to possible test control material degradation or instrument malfunction. A microcomputer-based program package is described, designed to reduce the errors and lengthy preparation inherent in the manual generation of such a report. Quality-control summary data is automatically compared with a predefined set of statistical criteria, and any aberrant values are flagged, thus eliminating subjective and nonuniform data interpretation. Statistical comparisons include: number of control points, delta mean, delta standard deviation, standard deviation index, and F-ratio. The summary report is well accepted by the laboratory staff, and its incorporation into the decision-making process allows for an efficient, critical, and uniformly rigorous examination of analytic proficiency.

Chemistry, Clinical↗
PubMed1991

Quality control programme for the preparation of small-pool lyophilized heat-treated cryoprecipitates.

International and national documents on and standards for quality control have been introduced for Blood Banks. Recently, the Standard Registration Document and a National Health Authority Licence for factor VIII preparations based on the Document were introduced in the Netherlands. In the course of developing a preparation of lyophilized heat-treated cryoprecipitates in our Blood Bank, we used this Standard Registration Document and the good pharmaceutical manufacturing practices to design a quality control protocol. The aim of this protocol was to provide documented evidence on the quality of both our product and the production process. The protocol included the validation or revalidation of individual installations and procedures used during production, validation of the whole process and quality control of routine production. With our quality protocol we have been able to demonstrate that our preparation is consistently of the intended quality.

Blood Component Removal↗
PubMed1996

Daily quality control programme in mammography.

The Medical Physics Department of S. Chiara Hospital (Trento, Italy) has developed, promoted and organized a quality control programme in mammography in the Department of Diagnostic Radiology. The aim of this paper is to describe the procedure for daily quality control carried out by the radiological technologist and analysed by the medical physicist, and also to discuss some interesting results obtained in the various departments during 1994. A sensitometric strip provides the film characteristic parameters to meet the requirements of DIN 6868 Part II (base plus fog level, average gradient, relative speed, maximum density, speed index and contrast index). A test phantom radiograph provides information on the detection of microcalcifications and simulated tumours (high and low contrast resolution) as well as on the central background density and the contrast. The exposure time-current product, mAs, needed to expose the phantom is always noted. Characteristic parameters of the two systems are compared with limiting values given by International Protocols or with the permissible ranges calculated in advance. It has been possible to discover variations in the performance of mammographic and automatic processing units due to the quality control programme. In one department, for example, the malfunctioning of the automatic exposure control device was observed. In another, replacement of mammography films and the automatic processing unit resulted in a better image quality.

Humans↗
PubMed1995

French national quality control for pH and blood gases: ten years experience.

A national quality control program for blood gas analysers has been established in France since 1983. Buffer solutions are used at two levels of pH, Po2, Pco2 for testing 950 laboratories using 22 different models. These annual programs inform about the accuracy and the precision of the instruments. They also make the user conscientious to different procedures of quality control. Information is also obtained on the yearly turnover of the types of analysers.

Blood Gas Analysis↗
PubMed2005

[Organization of support and quality control of medicaments in Russian Federation Armed Forces medical service].

The article presents the chronological analysis of formation of the system for providing the medicament quality control in the medical service of Russian Federation Armed Forces. The role of Centers of medicament quality control and certification in the State system for providing medicament quality is demonstrated. The aims of these Centers are to prevent the getting of poor and falsified medicaments into the troops. The practical work of the Centers during 4 years was analyzed. As the result 35 types of falsified and 97 types of poor medicaments were revealed. The proposals for improving medicament quality control in the medical service of RF Armed Forces are given.

Health Services Administration↗
PubMed1993

Determination of chromium in blood and serum: evaluation of quality control procedures and estimation of reference values in Danish subjects.

This paper describes analytical methods to estimate environmental and occupational exposure levels of chromium in blood and serum by Zeeman atomic absorption spectrometry. Also reported is an internal quality control procedure involving a combination of an online quality control and subsequent statistical evaluation of the quality control results to evaluate the performance of the analytical methods. The solubilization of the blood by the proteinase Subtilisin A resulted in a recovery of chromium of 106 +/- 4.5%; the uncertainty was approximately 10% at a chromium level of 1 microgram l-1. The detection limit (LOD) for chromium in serum was 0.17 micrograms l-1 and 0.20 micrograms l-1 for chromium in blood. The LODs were sufficiently low for the determination of chromium in a large fraction of reference populations not occupationally exposed. The present study indicates that reference values for chromium in blood and serum are low but within the range in recent investigations, i.e. 0.04-0.35 micrograms l-1 in serum and 0.12-0.34 micrograms l-1 in human whole blood. The fraction of reference values below LOD was between 0.45 and 0.57 for chromium in serum and blood. Consequently, the reference populations were described by distribution free one-sided tolerance intervals and the precision of the estimation of the tolerance intervals was expressed as coverage intervals. The 95% one-sided tolerance limit calculated for chromium in serum was 0.60 micrograms l-1 with the coverage interval (95 +/- 4.8) percent at a probability of 0.95. Thus, the probability was 0.975 that the tolerance interval covers at least 90.2% of the distribution. In addition, the probability was 0.025 that the tolerance interval covers more than 99.8% of the population. It was only possible to calculate the 90% tolerance interval for chromium in blood with the coverage interval at 0.90 probability. The one-sided tolerance interval for chromium in blood was 0.37 micrograms l-1 with the coverage interval (90 +/- 9.9) percent at a probability of 0.90.

Chromium↗
PubMed1986

Quality control in the blood bank.

In discussing quality assurance in the blood bank, where many of the standard statistical techniques of measuring accuracy simply do not apply, three questions come to mind: How much? How often? Who says? Because of severe changes in the prospective payment plan and a new interest in cost effectiveness, many transfusion services are re-examining blood banking methodologies and their relative usefulness in promoting patient well-being. Many serologists are beginning to say that "less is better." This concern for simplification and reduction of workload is reflected in the quality control.

Blood Banks↗
PubMed2006

Pretreatments of chromatographic fingerprints for quality control of herbal medicines.

Pretreatments of chromatographic fingerprints are important for quality control of herbal medicines and they include data correction and data transformation. The data correction can reduce the variations of experimental procedures, and data transformation can put different weights on the different parts of the fingerprints. In this paper, a new target peak alignment (TPA) procedure has been proposed to correct the retention time shifts, multiplicative scattering correction (MSC) has been introduced for response correction. Then the similarity of the fingerprints with mean and median fingerprints is used to evaluate the quality of herbal medicines (HMs). Furthermore, different data transformation methods with kernel principal component analysis (PCA) have been applied to the data and their effects were discussed. The proposed approaches have been demonstrated by the essential oils data set of a herbal medicine, named Houttuynia cordata (HC), containing samples from different geographic origins. The experimental results indicate that the proposed approaches may be helpful in the quality control of herbal medicines by fingerprints.

Chromatography, Gas↗
PubMed1995

[Results of a study of quality control of diagnostic ultrasound equipment].

AIMS: In this paper results of a quality control programme for B-mode ultrasound equipment used in clinical routine are presented. Over a period of 18 months 5 modern scanners with altogether 19 scanheads were periodically controlled. METHODS: The methods used for measuring the various performance parameters of an ultrasound equipment followed closely standard methods. All measurements were carried out with commercially available tissue-mimicking phantoms, and documented in a uniform protocol. RESULTS: Based on the results it was found that 11 of the scanheads did not operate correctly; 2 additional ones were severely defective. Only 6 scanheads were without loss of image quality or function. For the 13 malfunctioning scanheads adjustments, repair or even an exchange was necessary. CONCLUSION: The study demonstrates that quality control performed periodically is necessary to ensure optimal image quality and safe operation of the equipment.

Equipment Failure↗
PubMedDate not supplied

[SIN survey on quality control of dialysis water in Italy].

BACKGROUND: The importance of high quality water for dialysis is well established. This study aimed to obtain a picture of the Italian situation to develop national guidelines. METHODS: Questionnaire analysis was used to assess water quality control protocols and types of chemical and microbiological parameters monitored. Regions with responses from at least half the units were considered for the study. RESULTS: Eighteen out of 20 regions fulfilled the inclusion criteria; 297/469 dialysis units answered the questionnaire (5208 dialysis beds, 18213 patients). Eighty-one percent of Italian units follow a regular water quality control program. The reverse osmosis outlet is the sampling point used most for assessing chemical and microbiological parameters. The most common frequency in monitoring is < or =6 months. Fifteen chemical items, suggested by the Italian Farmacopea Ufficiale (FU), are periodically controlled by at least half the units. Aluminum is measured in about 70% of units, chloramines and volatile halogenated hydrocarbons, respectively, in 42 and 30% of units. According to the FU, bacterial counts at 22 degrees C (84%) and endotoxin determinations (60%) are the most common microbiological analyzes. CONCLUSIONS: The survey demonstrated protocol differences among the units, confirming the need for Italian guidelines to ameliorate and standardize dialysis water monitoring. More than half the units are following the FU, but we cannot rule out less strict monitoring only in non-participating units.

Hemodialysis Solutions↗
PubMed1976

A quality control program for the radioimmunoassay laboratory.

The major problems in applying quality control to radioimmunoassay measurements are (a) nonlinearity of the dose-response curve, and (b) nonuniformity of the residual variance. A logit-log transformation of the dose-response variables combined with an iterative weighted regression analysis appears to overcome most of the difficulties. This technic is particularly helpful when applied to substandard runs where extraneous standard points tend to distort assay results. The authors describe a quality control program that involves recording control values on calendar and histogram formats, monitoring assay variables by charting, and comparing the computer-calculated slope with the graphic plot to reveal "outliers." This program is useful in guiding technologists to locate possible causes for "out-of-limits" runs.

Computers↗
PubMed1992

Performance characteristics of a composite multivariate quality control system.

We present the results of an evaluation of the performance characteristics of a composite multivariate quality control (CMQC) system that incorporates quality control rules for univariate, multivariate, and correlation conditions. The CMQC system evaluated is designed to help analysts detect unacceptable trends and systematic error in one or more variables, unacceptable random error in one or more variables, and unacceptable changes in the correlation structure of any pair of variables. It is also designed to be tolerant of missing data, to allow analysts to reject as few as one or as many as all variables in a run, and to provide analysts with control statistics and graphics that logically relate to sources of analytical error. We show that the various components of the CMQC system have adequate statistical power to detect systematic errors, random errors, and correlation changes under the conditions likely to be encountered with multivariate analytical measurement systems: (1) a single variable with increased systematic or random error; (2) all variables or a subgroup of variables affected by a common problem that increases systematic or random error; and (3) missing data for one or more variables in a run. We also show that the power of the multivariate component of the CMQC system to detect systematic and random errors is higher than the power of an alternative multivariate test criterion.

Chemistry Techniques, Analytical↗
PubMed1990

External quality control in the andrology laboratory: an experimental multicenter trial.

An external quality control study for semen analysis was performed involving 10 andrology laboratories in geographically separate locations. For the evaluation of sperm concentration, eight samples with different concentrations, and for the assessment of sperm morphology three slides prepared from different semen samples were distributed. Sperm motility was evaluated in five samples delivered cryopreserved to the participants. The coefficients of variation (CVs) for sperm counts varied with the sperm concentrations showing highest variability for low and lowest for high concentrations (range 23% to 73%). The CV for sperm morphology ranged from 25% for normal heads to 87% for abnormal midpieces. The CV for motility of sperm was 21%. For comparison the mean CVs for internal quality control were as follows: 10% for concentration, 8% for morphology (normal heads), and 8% for motility.

Clinical Laboratory Techniques↗
PubMed2006

Radiation safety and quality control in the cyclotron laboratory.

Radiation safety was determined to maintain quality control in the cyclotron laboratory. Based on the results of 438 runs in the Faraday cup (20 microA for 10 min), 20 runs on 18O-water target (40 microA for 2 h) and 10 runs on 18O-gas targets (30 microA for 45 min), we have established that occupationally exposed workers remain 10 +/- 5 times below federal regulatory limits (FRLs) in the cyclotron vault, 30 +/- 8 times below FRL in the radiochemistry laboratory and 200 +/- 10 times below the FRL outside the cyclotron laboratory during beam operation. (The FRL for unrestricted area are <20 microSv in 1 h.) The non-occupationally exposed workers serving in offices in the vicinity of the cyclotron vault within 100 m distance remained 200 times below the FRL irrespective of beam being on or off, suggesting that routine beam operation of 40 microA for 2 h once a day during office hours is safe provided quality control and system performance measures as discussed in this report are strictly maintained.

Blood↗
PubMed1999

Experience with external quality control in spermatology.

Results are presented from participation in an external quality control (EQC) programme for semen analysis (UK NEQAS). Formalin-fixed semen samples and videotapes of motile spermatozoa were distributed four times a year over a 3-4 year period. Over the entire period there was close agreement for sperm concentration with, initially, the average of values from the other groups participating in the scheme, and later, values designated as reference values obtained from six laboratories of several chosen that consistently agreed with each other. The initial underestimation of the percentage of normal forms was abolished at the time of change in derivation of designated values and this largely eliminated the difference to establish closer agreement with the designated values. A consistent bias in the assessment of different categories of progressive sperm motility appeared to be resolved by a conscious decision to consider most spermatozoa as grade b and the exceptions as grade a, rather than the converse. Feedback of results to the technicians of the laboratory participating in an external quality control programme leads to reappraisal of subjective evaluation and to harmonization of results between laboratories.

Fixatives↗