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PubMed2004

Fast high-performance liquid chromatography method for quality control of soy extracts.

Soy extracts contain a mixture of isoflavones belonging to the group of phytoestrogens. In the quality control of soy the amount of isoflavones, both aglycones and glycosides, is usually determined by means of reversed-phase HPLC-UV. On conventional C18-material columns, long analysis times are required in order to separate this complex mixture. In order to speed up analysis, the separation was optimized using two linked monolithic silica-based reversed-phase C18 columns. A spectacular decrease of the analysis time, i.e. almost three-fold, was achieved by applying a flow rate of 3-4 ml/min without loosing any separation efficiency. This analysis method for determination of isoflavones in soy extracts in less than 25 min was fully validated according to the ICH guidelines.

Chromatography, High Pressure Liquid↗
PubMed1990

Medicaid program; Medicaid eligibility quality control (MEQC) program requirements--HCFA. Final rule with comment period.

This rule revises the regulations governing the Medicaid eligibility quality control (MEQC) program to include more specific program requirements and to establish new timeframes for completing and reporting MEQC case findings to HCFA. The rule also establishes a performance-based threshold for States to meet before HCFA will consider good faith waiver requests of disallowance of Federal financial participation (FEP) in erroneous Medicaid payments and provides more definitive criteria for evaluating States' good faith efforts to meet the national standard error rate. In addition, the rule makes several technical changes and provides that a State may rebut its projected error rate only when it can present evidence that its projected error rate was based on erroneous data. These revisions will strengthen the basic MEQC program and provide flexibility and incentives to States to produce accurate Medicaid eligibility determinations.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1975

Proficiency testing, trouble shooting and quality control for the RPR test.

A Syphilis Serology Proficiency Testing Program revealed that 182 of the 272 (67 percent) participating laboratories failed to report acceptable results for a minimally reactive pair of serum samples. It was noted that serious technical errors involved the antigen, use of controls, procedures and in some cases, the lack of training. A program involving strict quality control measures is presented for use in routine syphilis serologic procedures.

Antigens↗
PubMed1995

A quality control study of CFTR mutation screening in 40 different European laboratories. The European Concerted Action on Cystic Fibrosis.

A quality control study was performed to determine the accuracy of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) mutation screening in 40 different genetic screening laboratories throughout Europe. A total of 9 different samples were investigated blindly by the participating laboratories. Only 25/40 laboratories, i.e. 62.5%, were able to type all samples correctly for the mutations for which they routinely screened. Only 2 of the 9 samples were correctly typed in all 40 laboratories. The lowest accuracy rate was 80% for 1 sample. 12.5% of the participating laboratories interpreted the F508C polymorphism as a true CF disease mutation and 23.5% interpreted the delta I507 mutation as a delta F508 mutation. For the delta F508 mutation, a false-negative result of 3.75% was obtained. It is clear that the accuracy of CFTR typing should be improved.

Cystic Fibrosis Transmembrane Conductance Regulato↗
PubMed1981

Alpha fetoprotein screening and diagnosis of fetal open neural tube defects: the need for quality control.

A workshop, held in May, 1978, at the National Institute of Child Health and Human Development, considered the quality control of reagents and assays for measuring alpha fetoprotein (AFP) in maternal serum and amniotic fluid for the antenatal screening and diagnosis of open neural tube defects. The recommendations, published in detail elsewhere and summarized in this article, were based on what was known to be readily achievable and on estimates of the effect of assay performance on screening and diagnostic sensitivity and specificity. Main points considered included: (1) choice of units for AFP measurement and interpretation, (2) need for National AFP Reference Preparations and the need for a scientific panel to assess the adequacy of these reference materials, (3) information needed from reagent manufacturers, (4) criteria for assay performance, (5) biological sources of reagents, (6) need for laboratory and epidemiologic monitoring, and (7) need for a minimum assay workload.

Amniotic Fluid↗
PubMed1998

Impact of quality control on accuracy in enzyme immunoassay testing for human immunodeficiency virus type 1 antibodies.

OBJECTIVE: To assess use of quality control (QC) material, supplemental to internal kit controls (calibrators), as protection against errors in enzyme immunoassay testing for human immunodeficiency virus type 1 antibodies. DESIGN: From August 1994 to January 1996, enzyme immunoassay testing accuracy was assessed for laboratories participating in the Centers for Disease Control and Prevention Model Performance Evaluation Program that provided information regarding their use of QC material. Error rates were examined for human immunodeficiency virus type 1 antibody-negative, strongly positive, and weakly positive samples. RESULTS: The overall error rate with QC (2.20%) was significantly (P = .0023) lower than the error rate without QC (2.90%). With QC use there was a significant reduction in the relative risk of error for negative (P = .014) and weakly positive (P = .0067) samples. After multivariate analysis, use of QC lowered overall error rate by 29% (P = .0009). Laboratories not using QC were at increased risk of systematic error. Following the Clinical Laboratory Improvement Amendments of 1988 guidelines for QC material was relatively more protective against error than lower frequencies/number of levels. CONCLUSIONS: Using QC protected against errors in enzyme immunoassay testing for human immunodeficiency virus type 1 antibodies. Two levels of QC should be used with each run as mandated by the Clinical Laboratory Improvement Amendments of 1988.

Clinical Laboratory Techniques↗
PubMed2026

QCatch: a framework for quality control assessment and analysis of single-cell sequencing data.

MOTIVATION: Single-cell sequencing data analysis requires robust quality control (QC) to mitigate technical artifacts and ensure reliable downstream results. While tools like alevin-fry and simpleaf (and augmented execution context for the alevin-fry), offer flexibility and computational efficiency to process single-cell data, this ecosystem will further benefit from a standardized QC reporting tailored for its outputs. RESULTS: We introduce QCatch, a Python-based command-line tool that generates comprehensive and interactive HTML QC reports designed specifically for single-cell quantification results. Taking the output directory of alevin-fry or simpleaf as the input, QCatch is able to perform essential processing steps, like cell calling, and generate detailed QC reports that contain informative visualizations and statistics, including unique molecular identifier (UMI) count distributions, sequencing saturation estimates, and splicing status information, for QC assurance. Built for seamless integration into downstream analysis workflows, QCatch exports the processed results in a richly-annotated H5AD format file, a widely used data format common among many downstream single-cell data analysis tools. AVAILABILITY AND IMPLEMENTATION: The source code and documentation of QCatch are available on GitHub at https://github.com/COMBINE-lab/QCatch. QCatch can be installed via both Bioconda and PyPI.

Single-Cell Analysis↗
PubMed1998

Consistency in quality control programmes for electron accelerators in radiotherapy centres.

BACKGROUND AND PURPOSE: To gain insight into the current practice of quality control (QC) of medical electron accelerators and to reduce possible variations in test frequencies and test procedures. MATERIALS AND METHODS: An extensive questionnaire on QC procedures of medical electron accelerators was distributed and completed by all (21) radiotherapy institutions in The Netherlands. The questions were related to safety systems, mechanical parameters, beam profiles, beam energy, absolute dosimetry, wedge filters, the dose monitor system and radiation leakage. The data of the questionnaire were compared with recommendations given in national and international reports on QC of electron accelerators. RESULTS: Large variations in time spent on QC exist, especially for accelerators having dual energy photon beams and several electron beam energies. This diversity is mainly due to differences in philosophy with regard to QC and the differences in resources and machine time available. Furthermore, large variations in test frequencies and test methodologies were observed. The staffing level involved in the QC measurements was evaluated and compared with recent recommendations provided by EFOMP-ESTRO. CONCLUSIONS: From these recommendations and the results of the questionnaire, a set of minimum guidelines for a QC programme could be formulated and implemented in all radiotherapy institutions in The Netherlands.

Guidelines as Topic↗
PubMed1992

[Logbook registration in slaughtering pig farms within the project Integrated Quality Control. II. Drug utilization in relation to clinical observation, farm conditions and prevalence of pathological findings].

During an Integrated Quality Control (IQC) project for finishing pigs, the application of veterinary drugs was registered by means of a logbook on 75 pig finishing farms. Investigated is as to how far the application of veterinary drugs to animals is linked up with clinical observations, management and climatic conditions on the farm and to what extent the application of veterinary drugs is linked up with the occurrence of pathological findings in pigs at the slaughterhouse. The results indicate that more veterinary drugs are used as there are more clinical findings on a pig farm. This is particularly true for the autumn-winter period. Farms that use more veterinary drugs have a higher percentage of pigs with pathological findings at the slaughterhouse. As the point of time of treatment of respiratory disorders is closer to the slaughter date, there is a higher percentage of pigs suffering from pneumonia at the slaughterhouse. Farms treating pigs in the first thirty days of the finishing period against intestinal disorders have a distinct higher percentage of pigs suffering from pneumonia at the slaughterhouse. It appears that less veterinary drugs are used at farms having specific housing and management characteristics.

Abattoirs↗
PubMed2002

RNA quality control: degradation of defective transfer RNA.

The distinction between stable (tRNA and rRNA) and unstable (mRNA) RNA has been considered an important feature of bacterial RNA metabolism. One factor thought to contribute to the difference between these RNA populations is polyadenylation, which promotes degradation of unstable RNA. However, the recent discovery that polyadenylation also occurs on stable RNA led us to examine whether poly(A) might serve as a signal for eliminating defective stable RNAs, and thus play a role in RNA quality control. Here we show that a readily denaturable, mutant tRNA(Trp) does not accumulate to normal levels in Escherichia coli because its precursor is rapidly degraded. Degradation is largely dependent on polyadenylation of the precursor by poly(A) polymerase and on its removal by polynucleotide phosphorylase. Thus, in the absence of these two enzymes large amounts of tRNA(Trp) precursor accumulate. We propose that defective stable RNA precursors that are poorly converted to their mature forms may be polyadenylated and subsequently degraded. These data indicate that quality control of stable RNA metabolism in many ways resembles normal turnover of unstable RNA.

Escherichia coli↗
PubMed1989

Results of the flow cytometry ACTG quality control program: analysis and findings.

The AIDS Clinical Trial Group's (ACTG) Immunology Committee was charged with initiating a quality control program for all laboratories participating in the ACTG program reporting flow cytometry data. Forty-one laboratories were evaluated. This report defines the goals of this program and the subsequent findings after 19 send-outs were made. Both HIV positive volunteer donors and normal age-matched donors were used. Sample sets included both heparin and EDTA anticoagulated bloods. Laboratories were asked to report hematologic parameters as well as flow cytometry data both in percentages and absolute numbers. Results were evaluated using nonparametric statistical analysis. Robust CVs and interquartile ranges were used to define the performance of individual laboratories for each CD subset analyzed. Intralaboratory reproducibility was analyzed by paired sample sets. All laboratories were found to be able to define normal samples as normal. Seventy-five percent of the laboratories were able to define abnormal samples as abnormal. Twenty-five percent could not identify two abnormal samples as abnormal. Forty percent of the labs were found unable to reproduce paired samples within an absolute of +/- 5%. EDTA was found slightly superior to heparin in bloods evaluated by flow cytometry within 30 hr of collection. The analysis of specific histograms, questionnaires, and data analysis led to a specific set of recommendations for performance of flow cytometry studies.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Quality control guidelines for testing cefotetan in the reference agar dilution procedure for susceptibility testing of anaerobic bacteria.

Reference values for quality control of in vitro susceptibility tests with cefotetan against anaerobic bacteria were determined in two independent multilaboratory studies with the approved National Committee for Clinical Laboratory Standards agar dilution method and three control strains (Bacteroides fragilis ATCC 25285, Bacteroides thetaiotaomicron ATCC 29741, and Clostridium perfringens ATCC 13124). The results of the two studies were in agreement. The recommended MIC control limits for B. fragilis ATCC 25285 and B. thetaiotaomicron ATCC 29741 are 4.0 to 16 micrograms/ml and 32 to 128 micrograms/ml, respectively. MICs for C. perfringens ATCC 13124 were too variable to be useful for controlling tests with cefotetan.

Bacteria, Anaerobic↗
PubMed2005

Who's really hypertensive?--Quality control issues in the assessment of blood pressure for randomized trials.

The characterization of blood pressure in treatment trials assessing the benefits of blood pressure lowering regimens is a critical factor for the appropriate interpretation of study results. With numerous operators involved in the measurement of blood pressure in many thousands of patients being screened for entry into clinical trials, it is essential that operators follow pre-defined measurement protocols involving multiple measurements and standardized techniques. Blood pressure measurement protocols have been developed by international societies and emphasize the importance of appropriate choice of cuff size, identification of Korotkoff sounds, and digit preference. Training of operators and auditing of blood pressure measurement may assist in reducing the operator-related errors in measurement. This paper describes the quality control activities adopted for the screening stage of the 2nd Australian National Blood Pressure Study (ANBP2). ANBP2 is cardiovascular outcome trial of the treatment of hypertension in the elderly that was conducted entirely in general practices in Australia. A total of 54 288 subjects were screened; 3688 previously untreated subjects were identified as having blood pressure >140/90 mmHg at the initial screening visit, 898 (24%) were not eligible for study entry after two further visits due to the elevated reading not being sustained. For both systolic and diastolic blood pressure recording, observed digit preference fell within 7 percentage points of the expected frequency. Protocol adherence, in terms of the required minimum blood pressure difference between the last two successive recordings, was 99.8%. These data suggest that adherence to blood pressure recording protocols and elimination of digit preferences can be achieved through appropriate training programs and quality control activities in large multi-centre community-based trials in general practice. Repeated blood pressure measurement prior to initial diagnosis and study entry is essential to appropriately characterize hypertension in these elderly patients.

Aged↗
PubMed1987

Quality control of murine monoclonal antibodies using isoelectric focusing affinity immunoblot analysis.

Quality control of murine hybridoma secretory products was performed using two variations of the isoelectric focusing affinity immunoblot analysis. The first approach employed antigen-coated nitrocellulose placed on top of an acrylamide gel containing isoelectrically focused ascites to bind antigen specific monoclonal antibody (MoAb). Murine antibody bound to the insolubilized antigen was then detected with enzyme-conjugated anti-mouse IgG. In a second variation, focused ascites proteins were passively blotted onto nitro-cellulose and specific monoclonal antibody was detected with enzyme-conjugated antigen. Several batches of ascites containing anti-human IgG antibodies that were produced by 6 hybridomas over a 1-3 year period were assessed by IEF-affinity immunoblot analysis. Both immunoblot approaches permitted effective monitoring of immunoreactive antibody for pI microheterogeneity. IEF-affinity immunoblot patterns of unprocessed ascites displayed specific MoAb banding patterns with narrow pI ranges (less than or equal to 0.6 pH units), in contrast to the reported 5.5-8.0 pI range of polyclonal mouse IgG. Banding patterns obtained in the IEF affinity immunoblot typically displayed 3-5 major dense bands flanked by 2-4 minor fainter bands. Batches of ascites obtained years apart produced similar immunoblot patterns, indicating constant antibody production and confirming the stability of these hybridoma clones. Minor bands appeared in 2 earlier lots of ascites, suggesting possible modification of antibody during storage. IEF affinity immunoblot analysis is a useful tool for monitoring MoAb pI microheterogeneity as an indicator of antibody quality without the need for isolation of monoclonal antibody from culture medium or ascites.

Animals↗
PubMed1993

A quality control system involving peer review of abnormal cervical smears.

An internal quality control system which is used in the centralized cytology laboratory of a population-based cervical cancer screening programme in Florence is described. It includes a peer review procedure. Abnormal cervical smears are circulated among all the cytologists and a consensus on the final diagnosis is reached. This daily procedure is designed to evaluate the performance of each cytologist and of the laboratory as a whole but can also be considered a valuable training opportunity. During an 18-month period 1197 smears were reviewed by 15 readers using a reporting form with six main categories of reporting (from 'negative' to 'invasive carcinoma'), plus an 'unsatisfactory' category. Overall the concordance between the 15 cytologists, assessed using the kappa statistic (range 0.46-0.71; median 0.60), was good. The level of agreement increased when a weighted kappa statistic (range 0.55-0.78; median 0.68) was used. Kappa values were also calculated for specific categories and suggested an increasing concordance with increasing severity of the lesions, the categories of 'severe dysplasia' and 'invasive carcinoma' showing the highest agreement. The poor results for the 'moderate dysplasia' confirmed the need for combining this group with the 'severe dysplasia', as proposed in the Bethesda system.

Female↗
PubMed1987

[Evaluation of the control quality of arterial hypertension over a 10-year period at a hemodialysis center].

Using the "Diaphane" computed medical record system enables multicentric statistical studies to be conducted. With this system, the quality of arterial hypertension control (supine systolic and diastolic arterial pressure before and after dialysis) was evaluated over a 10-year period in chronic haemodialysis patients in comparison with a multicentric population. A continuous statistical study of the results showed a regular voluntary decrease in arterial pressure. The evaluation of the quality of medical care represented by this comparison contributes to a therapeutic improvement.

Adult↗
PubMed2003

Recognition of a single transmembrane degron by sequential quality control checkpoints.

To understand the relationship between conformational maturation and quality control-mediated proteolysis in the secretory pathway, we engineered the well-characterized degron from the alpha-subunit of the T-cell antigen receptor (TCRalpha) into the alpha-helical transmembrane domain of homotrimeric type I integral membrane protein, influenza hemagglutinin (HA). Although the membrane degron does not appear to interfere with acquisition of native secondary structure, as assessed by the formation of native intrachain disulfide bonds, only approximately 50% of nascent mutant HA chains (HA(++)) become membrane-integrated and acquire complex N-linked glycans indicative of transit to a post-ER compartment. The remaining approximately 50% of nascent HA(++) chains fail to integrate into the lipid bilayer and are subject to proteasome-dependent degradation. Site-specific cleavage by extracellular trypsin and reactivity with conformation-specific monoclonal antibodies indicate that membrane-integrated HA(++) molecules are able to mature to the plasma membrane with a conformation indistinguishable from that of HA(wt). These apparently native HA(++) molecules are, nevertheless, rapidly degraded by a process that is insensitive to proteasome inhibitors but blocked by lysosomotropic amines. These data suggest the existence in the secretory pathway of at least two sequential quality control checkpoints that recognize the same transmembrane degron, thereby ensuring the fidelity of protein deployment to the plasma membrane.

Amino Acid Sequence↗
PubMed1990

A simulation study of the Westgard multi-rule quality-control system for clinical laboratories.

A particular version of the Westgard-Barry-Hunt-Groth (Westgard) multi-rule quality-control system is studied by Monte Carlo simulation. The principal focus is on the amount of distortion in the working power curve caused by skewness in the distribution of analyte measurements. The effect of using only the first two rejection modes of the Westgard system is also studied.

Computer Simulation↗