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PubMedDate not supplied

Multicenter study of an erythro-aggregometer: quality control and standardization.

There is a need for quality assurance procedures in hemorheology, especially for clinical and pharmacological studies, which require reliable and well-calibrated instruments to be interpretable and comparable. Preliminary investigations allowed preparation of standardized SM (normal NS and hyperaggregable HS), and checking of storage conditions (in accordance with the guidelines of the SSC of ISTH) of RBC in nutritive SAG mannitol for at least 2 or 3 weeks with subsequent washings and resuspension in SM. In our study, we compared erythro-aggregometers of the same brand in 6 laboratories, using the same red blood cells (RBC) and suspending media (SM) for each series of tests. EA was measured by laser backscattering with determination of aggregation time (AT), partial dissociation threshold (PDT) and aggregation index (AI). Prior to the study, devices were set up on the same day with the same standardized blood, and calibration data were then analyzed. Within-assay precision (WAP) was assessed on 3 days for the 2 types of SM (n = 18 x 2). Between-assay precision (BAP) was assessed on 6 occasions, once every month (n = 6 x 2 x 6). Accuracy was studied with 3 series of RBC resuspended in 10 SM of "unknown" aggregability. Good agreement was observed between 5/6 centers for the 3 parameters of EA. WEP was good: CV of AT ranging from 1.4 to 2.5% for the NS and from 1.4 to 2.4% for the HS. In each center, BAP was slightly lower than WEP (CV: 8-11.8% for the NS and 3.8-4.7% for the HS over the 6-month study), with no drift, except for one center. Precision was always better with the HS than with the NS which seemed a better tool to assess it. As to accuracy, non-significant differences were generally found between centers, with similar data to the reference values. This work also stressed the importance of the RBC parameter itself in rheological data. For the first time, a protocol for standardization of EA has been developed and evaluated, permitting the Quality Control of this technique.

Analysis of Variance↗
PubMed1978

Technical quality control in histopathology.

A pilot scheme for technical quality control in histopathology is described. The test material used and the methods of assessment and reporting are detailed. The scheme outlines not only interlaboratory comparison of technical performance but also provides a method of sharing uncommon material.

Hospital Departments↗
PubMed1998

Limitations and requirements for quality control of sputum smear microscopy for acid-fast bacilli.

Sputum microscopy for acid-fast bacilli (AFB) is considered to be the most appropriate method for case-finding in a tuberculosis (TB) control programme. It is usually carried out by general technicians, often after minimal training. Quality control of their results therefore seems indispensable. The methods advocated for quality control are reviewed. Controls by culture leave too much uncertainty because of big differences in technical characteristics of the methods. Sets of smears sent out by a central laboratory can only be used to assess capability. Rechecking routine smears allows daily performance to be appraised and may be a strong motivation, but feasibility may be a problem. Based on our experience, we describe the technical requirements for cross-checking of routine smears. Counter-checking slides with discordant results is crucial for accurate assessments. A sample size should strike a balance between statistical accuracy and the man-power needed. Indicators for evaluation are proposed that allow discrimination of error gradings, to be used in a phased manner with priority at first being given to false negatives and false positives that pass the threshold for clinical decision-making. Estimates of critical values with suggestions about their interpretation are placed in the context of supervising TB laboratories.

Bacteriological Techniques↗
PubMed2004

Quality control of herbal medicines.

Different chromatographic and electrophoretic techniques commonly used in the instrumental inspection of herbal medicines (HM) are first comprehensively reviewed. Chemical fingerprints obtained by chromatographic and electrophoretic techniques, especially by hyphenated chromatographies, are strongly recommended for the purpose of quality control of herbal medicines, since they might represent appropriately the "chemical integrities" of the herbal medicines and therefore be used for authentication and identification of the herbal products. Based on the conception of phytoequivalence, the chromatographic fingerprints of herbal medicines could be utilized for addressing the problem of quality control of herbal medicines. Several novel chemometric methods for evaluating the fingerprints of herbal products, such as the method based on information theory, similarity estimation, chemical pattern recognition, spectral correlative chromatogram (SCC), multivariate resolution, etc. are discussed in detail with examples, which showed that the combination of chromatographic fingerprints of herbal medicines and the chemometric evaluation might be a powerful tool for quality control of herbal products.

Chromatography↗
PubMed2004

A graphical approach for quality control of oligonucleotide array data.

In studies of quality control of oligonucleotide array data, one objective is to screen out ineligible arrays. Incomparable arrays (one type of ineligible arrays) arise as the experimental factors are poorly controlled. Due to the high volume of data in gene arrays, examination of array comparability requires special treatments to reduce data dimension without distortion. This paper proposes a graphical approach to address these issues. The proposed approach uses percentile methods to group data, and applies the 2D image plot to display the grouped data. Moreover, an invariant band is employed to quantify degrees of array comparability. We use two publicly available oligonucleotide array datasets from Affymetrix GeneChip System for evaluation. The results demonstrate the utility of our approach to examine data quality and also as an exploratory tool to verify differentially expressed genes selected by vigorous statistical methods.

Algorithms↗
PubMed1997

Quality control phantom for digital chest radiography.

PURPOSE: To develop and test a chest phantom for routine quality control testing of digital radiography systems. MATERIALS AND METHODS: The phantom was constructed from sheets of copper, aluminum, and acrylic, which were cut and arranged to yield a radiographic projection resembling that of a human thorax. Regional test objects allowed quantitative assessment of optical density, contrast detail, and spatial resolution. Validation tests were performed to assess image stability in a stable imaging environment and sensitivity to changes in image quality when they occur. RESULTS: The phantom yielded consistent pseudoclinical images when used in a routine quality control program and facilitated detection of simulated problems that were induced in imaging system performance. CONCLUSION: The chest phantom enables quantitative, full-system testing of digital radiography system as they are used clinically for chest radiography.

Humans↗
PubMed1992

A multiyear quality control study of alpha-track radon monitors.

Quality control exposures of commercial alpha-track radon monitors have been conducted approximately weekly at the U.S. Department of Energy (DOE) Grand Junction Projects Office since early 1987 in support of DOE remedial action programs. The results of these exposures provide a historical record of the comparative performances of these radon monitors.

Government Agencies↗
PubMed1971

Quality control in bacteriology: preliminary trials.

Six trials of quality control material sent in the form of artificial specimens are reported. A method of assessment using a computer for complex results, including antibiotic sensitivity tests, was employed. The trials were successful in showing the need for a comprehensive service and in bringing to light by this method a wide variety of errors.

Bacteriological Techniques↗
PubMed1988

Effect of storage temperature and shaking rate on pH and blood-gas results for two quality-control products.

Directions for pre-analytical handling of ampules of two commercially available aqueous quality-control products (contrlL and G.A.S.) contain vague instructions such as "store at room temperature" and "shake vigorously" before analysis. We examined the effect of different storage temperatures (25, 31, and 38 degrees C) and shaking rate (one, two, and four shakes per second) on pH and blood-gas results. For both products, increasing the storage temperature significantly decreased pO2 results, the magnitude of the bias being greatest for those solutions with the highest O2 tensions. However, increasing the shaking rate partly offset this bias. Increasing storage temperature also decreased results for pCO2 and increased results for pH for both manufacturers' ampules with the highest CO2 tensions, and this bias was not offset by increasing the shaking rate. We conclude that both storage temperature and shaking rate must be precisely defined and carefully monitored before these products are used in a quality-control program.

Blood Gas Analysis↗
PubMed2003

Two birds with one stone: a novel motif for ACh receptor assembly quality control.

Assembly of ACh receptors is under tight quality control. Only functional ACh receptors are expressed on the cell surface; unassembled subunits are retained in the endoplasmic reticulum (ER). In a recent elegant study, Wang and colleagues have identified a novel motif in the M1 domain of the ACh-receptor subunit that is responsible for ER retention and degradation of unassembled subunits. This signal appears to play an important role in regulating surface trafficking of functional ACh receptors.

Amino Acid Motifs↗
PubMedDate not supplied

[A method of quality control in thermoluminescent dosimetry].

This work suggests a quality control method for thermoluminescent dosimetry. For each set of dosemeters, read-out has been made at increasing values of dose, on the base of predetermined conditions in different read-out techniques and from different operators. The statistical analysis of each possible group of T.L.D. permitted us to draw the error-response curves and the relative precision profiles and to select the best evaluation techniques and the best operator on the base of precision, sensitivity and useful range.

Dose-Response Relationship, Radiation↗
PubMed1994

[Hypotonic shock reaction as quality control marker for platelet concentrates].

Ten years of quality control in routine have led to a standardized platelet concentrate (PC). Mean parameters of the preparations are in the range of pH 6.7-7.3, (1.0-1.5) x 10(9)/ml platelet concentration, 80 x 10(9) platelets/PC and 2 x 10(7) leukocytes/PC. To judge the function of PCs, three methods were compared: the morphologic score, platelet aggregation tests, and the hypotonic shock reaction. The result is: The hypotonic shock reaction is a simple, well reproducible and sensitive method to judge the cell integrity.

Blood Platelets↗
PubMed1985

Inter-laboratory quality control in neonatal screening for inborn errors of metabolism.

Screening of neonates for inborn errors of metabolism has been carried out on a national level since 1969 in the Federal Republic of Germany. To raise the reliability of these routine investigations, we introduced an external quality control in March 1982. Every 2 months ten filter paper samples were sent to the screening centres in West Germany. Some of these samples have a normal and others a slightly raised content of phenylalanine, leucine, methionine and galactose. The success of this external quality control is appraised on the basis of the number of false negative results. In the course of time, screening centres in France, Israel, Italy, Japan, Switzerland, Taiwan, Turkey and Yugoslavia have also participated in these inter-laboratory quality controls.

Diagnostic Tests, Routine↗
PubMed1975

A preserved leukocyte preparation for quality control.

A preparation technic for stabilized leukocytes for quality control is described. Human leukocytes are separated from 5 ml. of blood using dextran; the erythrocytes are lysed with isotonic NH4Cl-Tris buffer, pH 7.2. The washed leukocytes are resuspended in 50 ml. of cacodylate HCl buffer, pH 7.4. Five ml. of 2.5% glutaraldehyde were slowly added, and preservation is accomplished by storage overnight at 4 C. The washed leukocytes are resuspended in physiologic saline solution containing 1:1,000 sodium azide, then stored at 4 C and at room temperature. The preparations were highly stable at both temperatures for at least 3 months, as indicated by both manjal and electronic leukocyte counts.

Azides↗
PubMed2001

Quality control of resident operative experience: compliance with RRC criteria.

PURPOSE: Process Capability Analysis (PCA) is a quality control tool that can be applied to how resident cases are allocated. PCA measures how close an output is to its target (Cp) and its location (K) in relation to Cp. For resident cases, the statistics of Cp and K measure variability in case numbers, which is useful in planning how a program meets RRC criteria in operative experience on specialty services. METHODS: A review of 6 years of vascular surgery cases (1994-1999) using PG 5 RRC case logs and the departmental quality database as sources was done. PCA was applied to resident case numbers. RRC 1997-1998 National Program Data were used to define quality control limits. The 30th, 50th, and 70th percentiles in vascular procedures served as lower, nominal, and upper control limits, respectively. RESULTS: Cases were grouped into aortic (AO), cerebrovascular (CER), peripheral (PER), and visceral (VSC), to meet RRC definition for major reconstructions. PCA analysis of PG5 RRC submitted data, total cases reported by the graduating residents (n = 20) in their submitted RRC Case logs, and department QA log numbers over 6 years of the period revealed the following mean numbers for AO = 13.7 +/- 4.2 (Cp = 0.279, K = +70.5%), CER = 15.6 +/- 6.4 (Cp = 0.365, K = +78.6%), PER = 23.1 +/- 10.5 (Cp = 0.237, K = +80.1%), VSC = 2.5 +/- 1.5 (Cp = 0.189, K = +175.0%), and total = 55.1 +/- 20.2 (Cp = 0.305, K = +70.5%). CONCLUSIONS: Processes that are in statistical control should have a Cp > 1.0, and a small K: i.e., centered tightly and near the desired nominal limit. By PCA analysis, the vascular surgery service product of PG5 case numbers is not in statistical control, but instead exceeds the defined control limits (RRC 50th percentile levels). The low Cp values demonstrate that specific case numbers may vary from resident to resident. The high positive K percentages imply that more residents have case numbers that meet or exceed RRC 50th percentiles. Sources of potential error and variability may be partially explained by the data of total case volume and resident underreporting. More accurate RRC reporting by residents could account for up to 20% more cases, potentially offsetting individual case allocation differences within a particular resident year.

Aorta↗
PubMed1992

Quality control of surgical technique in a multicenter, prospective, randomized, controlled study on the surgical treatment of gastric cancer.

To evaluate the effect of lymph node dissection on gastric cancer patients operated upon with curative intent, we are carrying out a multicenter, prospective, randomized, controlled study in the Netherlands. The trial compares conventional gastrectomy to gastrectomy with extended lymph node dissection. In the first four months, a Japanese supervisor attended all the extended surgery and instructed many Dutch surgeons, including the eight consulting surgeons; since then, all extended gastrectomies have been attended by one of the consulting surgeons. The study coordinator attended all conventional cases. This assured that the quality of the extended surgery was as good as the Japanese standard, of which excellent results have been reported. To achieve this quality control, randomization before surgery was obligatory for practical reasons. Curability assessment at laparotomy, however, is done quite objectively with histological proof, except for the judgement of irresectability. Although this has resulted in many non-curative cases being randomized but subsequently not given the allocated surgery, the sample size should be sufficient to allow analysis according to randomization or the initial "intention to treat." This is the first protocol for a multicenter trial in surgical oncology to have such excellent surgical quality control and to assure a quality as high as that in the original report with uniformity in the level of technique. In studies comparing surgical techniques, it is vital that attention should be given to surgical quality control, otherwise survival rates may show little improvement and fail to make any impact on surgical practice.

Adenocarcinoma↗
PubMed2003

[Quality control of recombinant adeno-associated virus type 2/human blood coagulation factor IX].

AIM: To establish quality control requirements and methods for recombinant adeno-associated virus(rAAV) type 2/human blood coagulation factor IX (rAAV-2/hFIX). METHODS: Identification of rAAV genome fragments, potential contaminants including wild type AAV(wtAAV) and helper virus, were detected by PCR. Purity of rAAV-2/hFIX was analyzed by cation-exchange HPLC and SDS-PAGE. Virus partical numbers were performed by dot blot assay. hFIX expression was demonstrated by ELISA and potency of hFIX was verified by APTT. RESULTS: Identity of rAAV-2/hFIX was proved. Residues of wtAAV and helper virus were conformed to requirements. Purity of rAAV-2/hFIX were more than 98%. Partical numbers of rAAV-2/hFIX were more than 1.0 x 10(15) VG.L-1. hFIX expression was more than 20.0 micrograms.L-1. hFIX potency was verified by APTT following rAAV-2/hFIX injected to FIX gene knockout mice, potency results conformed to requirements. CONCLUSION: The methods and requirements had been established for quality control of rAAV-2/hFIX.

Animals↗