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 811 records · Page 45Linked to original sources
PubMed2001

K statistic as a measure of quality control in cervicovaginal cytology.

Quality assessment schemes are widespread in most branches of pathology but are uncommon in the more subjective areas of histopathology and cytology. Researchers in many fields have become increasingly aware of the observer as an important source of measurement error. The validity of any method of reporting evidence of an abnormal process in cellular material is based on the degree of correlation with the actual disease process as it exists in the tissue and its reproducibility. Correlations can be tested in retrospective studies in which diagnoses based on cellular evidence are matched against the disease process present in biopsy specimens. Correlations can also be tested by examination of a set of unknown cellular preparations obtained in the presence of proven disease. While reproducibility is indirectly related to correlation, it is meant to imply satisfactory utilization of the method by other groups of cytotechnologists and cytopathologists. While cytopathology will continue to play an important role as a screening technique for the detection of cancer of the uterine cervix, its usefulness in the study of the early manifestations of the disease process is yet to be realized on a universal basis.

Cervix Uteri↗
PubMed2005

Pseudocontamination of blood components with Burkholderia cepacia during quality controls.

We report on a pseudooutbreak of Burkholderia cepacia because of the use of a contaminated disinfectant during quality controls in a university blood bank. No septic reactions associated with transfusions had been reported in patients over the last 6 months. Analysis of the individual quality control procedures showed that a disinfectant based on a quaternary ammonium compound (QAC) had been used in order to disinfect the rubber stopper of the blood culture bottle. B. cepacia was found in a sample taken from this disinfectant, which was prepared with concentrate and tap water according to the manufacturer's instructions. The four isolates (one in disinfectant and three in blood components) were found to be identical in their biochemical reactions and resistance patterns. QAC-based disinfectants are not efficacious against a part of the spectrum of gram-negatives and are therefore inadequate. After introduction of an alcohol-based preparation, no more cases of B. cepacia contamination have been identified.

Blood Component Transfusion↗
PubMed1984

Liquid and lyophilized quality-control materials compared for use in continuous-flow analysis.

Using a Technicon SMAC continuous-flow instrument, we compared a liquid quality-control material ("Decision level 3," Beckman) with two different lyophilized quality-control materials. The variances for 19 analytes in the three materials were significantly greater for Decision than for the Ortho Abnormal and the Omega II lyophilized control sera (p less than 0.00001 for each comparison by the omnibus test). The imprecision for Decision was not due to incomplete mixing or carryover. The viscosity of Decision, however, was more than twice that of the two lyophilized control sera or of pooled human serum.

Autoanalysis↗
PubMed1986

Identification of interference affecting the gas-liquid chromatography analysis of valproic acid in quality control material.

The matrix used to prepare control material for the Chemical Pathology Quality Assurance Programme Group of the Royal College of Pathologists of Australasia/Australian Association of Clinical Biochemists (RCPA/AACB) was investigated to identify a contaminant affecting the gas-liquid chromatography (GLC) analysis of valproic acid (VPA). The contaminant, not present in patients' sera, eluted with the octanoic acid internal standard in our GLC procedure. The compound was identified as octanoic acid. The source of this contamination could not be determined. The presence of endogenous octanoic acid in the RCPA/AACB quality control material precluded the use of octanoic acid as an internal standard.

Chromatography, Gas↗
PubMed2004

Internal quality control of a turbidimetric immunoassay for canine serum C-reactive protein based on pooled patient samples.

BACKGROUND: Optimized internal quality control (IQC) procedures are important to ensure that only results without medically important errors are used for medical decision-making and to ensure that unnecessary rejection of valid analytical runs is avoided. Additionally, estimates of the analytical performance can be derived from IQC data. In the absence of available species-specific standards of a compound, the use of alternative control materials based on patient samples is a possibility, although investigations on the suitability of this approach are needed. OBJECTIVES: The objective of the study was to plan and implement a simple IQC procedure with control material based on pooled canine serum samples for a turbidimetric immunoassay (TIA) for the determination of human C-reactive protein (CRP) that recently was validated for the determination of canine serum CRP, and to assess the clinical analytical performance of the assay. METHODS: Proposed guidelines for the planning and implementation of IQC procedures were followed by using 2 control materials. Quality requirements of the assay were defined objectively by means of available data on biological variation, and goals for IQC performance were defined according to recommendations (probability of error detection [P(ed)] >.90 and of false rejection [P(fr)] <.05). Analytical performance was evaluated by means of medical decision charts. RESULTS: The control rule of 1(2.5s) (ie, rejection of the analytical run if at least 1 of 2 control materials deviates from the mean by more than 2.5 SD) fulfilled the criteria of predicted IQC performance (P(ed) =.94-1.00, P(fr) =.03). The IQC method was successfully implemented over a 14-week period. The observed coefficient of variation in the period of monitoring was 3.8% (low) and 2.9% (high), which equals excellent analytical performance. CONCLUSIONS: It was possible to plan and implement a simple IQC procedure for the CRP-TIA with control materials based on canine serum samples that fulfilled the criteria of high error detection and low false rejection of valid analytical runs. The assay showed excellent long-term analytical performance over a 14-week period.

Animals↗
PubMed2002

[Quality control program in a group of Spanish public hospitals (1993-2001)].

INTRODUCTION: The INSALUD (National Healthcare Institute) is a public institution that manages the provision of health services for 15 million Spanish people. INSALUD developed a quality control program for specialist care, which involved its 80 hospitals. OBJECTIVES OF THE PROGRAM: To promote leadership among the managers of quality assurance programs, to involve in the improvement of quality all the employees of the organization and to set out the Institution's following strategic outlines: to direct the services towards the needs of the population, to improve the quality and effectiveness of the care procedures, to minimize risks and to improve the information system. EQUIPMENT AND TECHNIQUES: The Management Contract, i.e. the main tool of specialist care management, included a Quality Control Program common to all the hospitals involved. The Program was divided in the following three parts: common improvement goals, monitoring of indicators and guidelines of the organization. OUTCOME AND FINDINGS: All the hospitals involved introduced their own quality assurance program which incorporated the Institution's Quality Control Program. The majority of the objectives assessed showed a continuous improvement of the outcome. The experience of the 1993-2001 INSALUD Quality program can prove to be very useful for the new Healthcare Services of the Autonomous Communities resulting from the decentralization of the healthcare provision of services in Spain.

Health Services Research↗
PubMed1998

Quality control of white cell-reduced red cells: white cell preservation and simplified counting.

BACKGROUND: White cell (WBC) degradation restricts the interval between the filtration process and the assay for residual WBCs. Maintaining WBC integrity would permit extended sample storage for batching and/or shipment to centralized laboratories. The usual quality control assay for WBC-reduced red cell units requires determining the number of WBCs in the entire counting area of a Nageotte hemocytometer, which consists of 40 rows. Reducing the counting area would simplify the quality control procedure. STUDY DESIGN AND METHODS: Adsol red cell units were prepared either on the day of collection (Day 0) or on Day 1 and WBC reduced by filtration on the same day. By using prefiltration and postfiltration red cells, samples containing WBC concentrations of 15, 10, and 3 WBCs per microL were prepared by serial dilution. Identical samples were treated with glutaraldehyde and stored at either 20 to 24 degrees C or 1 to 6 degrees C. All samples were assayed on the day of component preparation and on Days 7 and 14. The numbers of WBCs corresponding to 10- and 40-row areas of the Nageotte hemocytometer were determined. RESULTS: For the conditions and WBC concentration range studied, no significant changes in WBC concentrations were observed through Day 14 for glutaraldehyde-treated samples stored at either temperature, although there were substantial decreases in untreated samples. A 10-row measurement was determined to be sufficient for identifying WBC-reduced red cell units passing the present limit of 5 x 10(6) residual WBCs. CONCLUSION: Glutaraldehyde treatment can preserve WBCs in red cell samples at least up to Day 14, which provides increased efficiency in quality control for laboratories. Current red cell WBC-reduction filters produce components that, when assayed, contain fewer than 10 WBCs per full counting area. The simplified procedure would allow reduction of the counting area by 75 percent.

Blood Preservation↗
PubMed1986

Standardization and quality control of sperm concentration and sperm motility counts in semen analysis.

The paper reports a study of standardization and quality control of sperm concentration counts and visual motility assessments in human semen analyses performed for infertility investigations and from internal quality control procedures. Sperm concentration determinations were performed in Improved Neubauer haemocytometers on volumetric dilutions made using a positive displacement pipettor for sampling the liquefied semen. In addition to a standard 1 + 19 dilution a second dilution of either 1 + 9, 1 + 19 or 1 + 49 was made according to whether the estimated sperm concentration was less than 20, 20-100 or greater than 100 X 10(6)/ml respectively. The duplicate determinations of sperm concentration were highly significantly correlated (P much less than 0.001) with less than 5% variability. Parallel visual sperm motility assessments were made by two pairs of technicians and showed highly significant correlations (P much less than 0.001) between technicians in the determination of the percentages of motile and progressive spermatozoa as well as the subjective rating of sperm progressivity. When these values were incorporated into a calculated motility index which gave added weight to the progressive spermatozoa and to their quality of progression the correlations between technicians remained highly significant (P much less than 0.001) with average differences of the order of 1.0%. Therefore, provided that sufficient attention is paid to technician training, regular standardization checks and the use of only proven reliable procedures, quantitatively accurate values for sperm concentration and motility can be obtained in routine semen analyses.

Humans↗
PubMed2004

Study on quality control parameters of a TLD system for individual monitoring.

This work intends to identify and follow up quality control parameters important for the general improvement of our thermoluminescence dosemeter (TLD) system for Individual Monitoring that is currently preparing its accreditation according to the EN ISO/IEC 17025 Standard. A retrospective analysis of the readers' start-up tests revealed an eventual variation of parameters, like the high voltage, which may affect the light collecting system, and hence the TL dose results. This was investigated and although the high voltage requires a careful look, the stability and reproducibility of the TLD system was ascertained by the results of quality control procedures. As a consequence of this work, the start-up procedure was modified and the warning levels used for the start-up daily tests of the readers were derived from a more realistic approach.

Accreditation↗
PubMed2002

Internal quality control for erythrocyte sedimentation rate measured by TEST-1 Analyzer.

The TEST 1 is a fully automated analyzer for measurement of the erythrocyte sedimentation rate. This system employs a particular capillary where blood is moved by a special hydrodynamic system. This original method is not able to measure stabilized samples for quality control, probably because stabilized erythrocytes offer a higher resistance to movement into the capillary, giving a distorted sedimentation curve. We evaluated whether the stability of collected EDTA samples, as declared by the producer company, was sufficient to use samples measured the day before as internal quality control samples. We also evaluated whether different tubes could modify the test results between stored and fresh samples. The difference between ESRs measured in fresh and stored samples are non-relevant after 24h and 48h, using both the tubes considered. The agreement between fresh and stored samples was better than that obtained by comparison with the Westergren method and can be used for the internal quality control procedure.

Bias↗
PubMed2006

Post-test quality control for the single blood sample technique in glomerular filtration rate measurement in children.

BACKGROUND: While the value of the single blood sample (SBS) method for estimating 51Cr-EDTA plasma clearance has been repeatedly demonstrated, some nuclear medicine physicians are still reluctant to use it because of the lack of quality control parameters. PURPOSE: To present a post-test quality control procedure for the SBS technique in children. METHODS: In addition to the SBS clearance calculated using the specific paediatric SBS method, three artificial slope intercept (ASI) method clearances were calculated by assuming the distribution volume as, respectively, 20%, 25% and 30% of body weight. By dividing the injected activity by the distributional volume, the initial plasma concentrations (A0,30%, A0,25% and A0,20%) were calculated. Using these A0 values and the available single sample, ASI clearances were calculated by using the classical slope-intercept method. The working hypothesis of this approach was as follows. In the absence of significant errors, the three ASI clearance values should be close to that of the SBS method. This hypothesis has been tested using both simulated and patients' data. RESULTS: The results of the simulated study showed that an error in the injected dose produced variable differences between SBS and ASI clearances depending on the clearance values. The effect of an error on the plasma sample also varied as a function of the clearance values. The analysis of patient data revealed that the ASI approach allowed the identification of patients in whom the classical slope-intercept method suggested the presence of a possible error. CONCLUSION: A post-test quality control procedure for the SBS GFR measurement is presented. When the SBS clearance shows a difference with the ASI method (> 10 ml . min(-1) per 1.73 m2), the presence of an error is highly probable. A smaller difference, however, does not exclude erroneous data.

Child↗
PubMed2005

Developing a sustainable process to provide quality control materials for genetic testing.

PURPOSE: To provide a summary of the outcomes of two working conferences organized by the Centers for Disease Control and Prevention (CDC), to develop recommendations for practical, sustainable mechanisms to make quality control (QC) materials available to the genetic testing community. METHODS: Participants were selected to include experts in genetic testing and molecular diagnostics from professional organizations, government agencies, industry, laboratories, academic institutions, cell repositories, and proficiency testing (PT)/external Quality Assessment (EQA) programs. Current efforts to develop QC materials for genetic tests were reviewed; key issues and areas of need were identified; and workgroups were formed to address each area of need and to formulate recommendations and next steps. RESULTS: Recommendations were developed toward establishing a sustainable process to improve the availability of appropriate QC materials for genetic testing, with an emphasis on molecular genetic testing as an initial step. CONCLUSIONS: Improving the availability of appropriate QC materials is of critical importance for assuring the quality of genetic testing, enhancing performance evaluation and PT/EQA programs, and facilitating new test development. To meet the needs of the rapidly expanding capacity of genetic testing in clinical and public health settings, a comprehensive, coordinated program should be developed. A Genetic Testing Quality Control Materials Program has therefore been established by CDC in March 2005 to serve these needs.

Centers for Disease Control and Prevention, U.S.↗
PubMed1999

Improved quality-control detection of false-negative Pap smears using the Autopap 300 QC system.

Federally-mandated quality control (QC) in Papanicolaou (Pap) smear testing requires rescreening of 10% of negative smears, to include cases selected randomly as well as smears from patients that may have a higher risk for developing cervical cancer based on clinical information. FDA approval of NeoPath's AutoPap 300 QC system (NeoPath, Inc., Redmond, WA) allows practical QC rescreening of all negatives. We tested the ability of AutoPap to help increase identification of detection errors compared to random 10%/high-risk selection. From March 1-August 30, 1997, we utilized AutoPap/high-risk status to select cases for manual rescreen, and compared the rate of identification of primary screening errors to that for the preceding year using 10% random selection/high-risk status. Of 35,027 smears accessioned, 31,240 (89.1%) were screened as negative and 7,965 were selected for manual rescreen. Of these, 353 were determined to be abnormal. Most abnormals identified by this protocol were classified as atypical squamous or glandular cells of undetermined significance (ASCUS or AGUS). However, 59 low-grade squamous intraepithelial lesions (LSIL) and 13 high-grade squamous intraepithelial lesions (HSIL), many with few abnormal cells, were also identified. These results represented an increase in pickup rate of false negative due to detection errors of 2.3-, 2.8- and 5.6-fold for atypical squamous or glandular cells of undetermined significance, LSIL, and HSIL, respectively, when accounting for the volume differences over the time period measured. Our findings strongly support the conclusions drawn from clinical trials of the AutoPap that false negatives due to detection error can be significantly reduced when using AutoPap as part of a routine quality control program.

False Negative Reactions↗
PubMed2005

LC/MS fingerprinting of Shenmai injection: a novel approach to quality control of herbal medicines.

Chromatographic fingerprinting has been recommended as a potential and reliable strategy for the quality control of herbal medicines. Although varieties of chromatographic techniques, particularly HPLC, have been widely employed, hyphenated chromatographic approach has not been sufficiently exploited in chromatographic fingerprinting. In this work, LC/MS fingerprinting of Shenmai injection was developed. Thirty ginsenosides as well as seven ophioponins were selected to construct the LC/MS fingerprint using selective ion monitoring (SIM) mode, while previous HPLC fingerprint [H.J. Zhang, Y.J. Wu, Y.Y. Cheng, J. Pharm. Biomed. Anal. 31 (2003) 175-183] only represents the ginsenosides. Subsequently, the proposed LC/MS fingerprints were applied to identifying the product manufacturers. All the samples were accurately classified based on their LC/MS fingerprints in conjunction with principal components analysis (PCA). This study would be potentially helpful to improve the quality control ability of fingerprinting-based strategy for complex herbal medicines.

Central Nervous System Agents↗
PubMed1976

The role of regional quality control programs in the practice of laboratory medicine in the United States.

Since their initiation in 1967, Regional Quality Control Programs have expanded, and they are now accessible to all clinical laboratories in the United States. Based on input from large numbers of laboratories analyzing the same lots of control material for chemistry, hematology, and coagulation, the programs provide computer-generated intralaboratory statistics for day-to-day precision and interlaboratory comparative statistics for relative precision and accuracy. Nearly half the clinical laboratories in the United States currently participate in Regional Quality Control Programs in chemistry. These voluntary programs are coordinated by voluntary professional groups or by the manufacturers of control materials. Professionally directed programs are, for the most part, supervised by committees of state pathology societies.

Chemistry, Clinical↗