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PubMed1988

Use of "average of normals" quality control procedure in the detection and resolution of assay discrepancies.

Improved computer technology and imperatives for cost control have made the use of "average of normals" (AVON) procedure an attractive alternative to the more expensive standard quality control programs for clinical laboratory assay monitoring. The authors report the use of a version of the AVON procedure to resolve assay discrepancies with CO2 determination that the traditional quality control program appeared incapable of detecting. Their study suggests that the mean of patients within the reference interval (RI) is a sensitive indicator of accuracy, whereas the percentage of patients within RI is a good indicator of random imprecision.

Carbon Dioxide↗

PubMed1988

The seed stock concept and quality control for cell lines.

Procedures for the characterization of cell culture lines are reviewed. It is recommended that seed stocks be developed and that major quality-control efforts be applied first to those holdings, with essential tests repeated on cultures from working or distribution stocks prepared subsequently. Steps are taken throughout to ensure absence of microbial contaminants. Mycoplasma are especially troublesome. Investigators need also to be aware of potential endogenous viruses which may be hazardous or interfere with interpretation of results. Cell line species and absolute identities are established by fluorescent antibody staining, by determination of isoenzyme profiles, and by cytogenetic analyses. Additional characterizations will vary with cell type but may include tests for specific products, cytoskeletal proteins, tissue specific antigens, or immunoglobulins. Credentials of lines added to a collection plus representative cultures can be returned to the originators for concurrence before distribution. Advisory committees may be established as circumstance dictates to provide additional expertise regarding quality control for the specific collection being developed.

Cell Line↗

PubMed2002

[Quality control for recombinant adenovirus-IL2].

AIM: To investigate the quality and optimized test methods and establish the quality specification of recombinant adenovirus-IL2. METHODS: The titer of Adv-IL2 was measured by cytopathic effect (CPE). Hela cells were infected with Adv-IL2 in vitro, the expressed IL-2 and its bioactivity in Hela cell were determined by enzyme-linked immunosorbent assay (ELISA) and 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) respectively. The purity of Adv-IL2 was analysed by UV and IE-HPLC method. The molecular weight and enzyme digestive map of Adv-IL2 genome were analysed by electrophoresis. The characteristic gene E2B, IL-2 expression casseter and foreign factors (RCV, HIV, HBV, HCV) were detected with polymerase chain reaction (PCR). Other tests were carried out according to the Chinese Requirements for Biological Products. RESULTS: Adv-IL2 was generated efficiently with a titer of 3 x 10(10) pfu.mL-1. The expressed IL-2 and its bioactivity were 25 ng.mL-1 and 700 u.mL-1 respectively. A260 nm/A280 nm was 1.23. The purity determined by IE-HPLC was higher than 98%. The molecular weight, enzyme digestive map of Adv-IL2 genome, the characteristic gene E2B and IL-2 expression casseter conformed to expected values. CONCLUSION: The specification for Adv-IL2 is established and can be used for the quality control of the product.

Adenoviridae↗

PubMed1974

Regional quality control of coagulation assay procedures (normotest, simplastin-a and thrombotest).

The report is based on the first 8 months' operation of an extended regional quality control program involving 20 hospital laboratories in the Stockholm area. The test material was commercially available lyophilized human reference plasma containing uniformly reduced levels of factors II, VII and X, and optimal concentrations of fibrinogen and factor V. Each participant received 2 batches of the test material with different activity at each 4-week period. Participants were requested to analyze the specimens, independently and in duplicates, along with ordinary patient samples three times weekly during each period. The levels of the factors in the batches were changed in each period. The total number of reported results was 3113. The statistical analysis of values included the calculation of means and variances within and between different thromboplastins (Normotest, Simplastin-A, Thrombotest), different techniques (venous and capillary blood, automatic and manual end-point determination), and laboratories classified according to the category and number of personnel and of performed coagulation tests. Systematic differences between thromboplastins, techniques and laboratories, even using the same type of thromboplastin, contributed a significantly greater amount than within-laboratory random variation to the total variation of determinations. The obtained results indicate the urgency of the quality control of coagulation activity tests.

Analysis of Variance↗

PubMed2003

Cleavage of the A site mRNA codon during ribosome pausing provides a mechanism for translational quality control.

Cells employ many mechanisms to ensure quality control during protein biosynthesis. Here, we show that, during the pausing of a bacterial ribosome, the mRNA being translated is cleaved at a site within or immediately adjacent to the A site codon. The extent of this A site mRNA cleavage is correlated with the extent of ribosome pausing as assayed by tmRNA-mediated tagging of the nascent polypeptide. Cleavage does not require tmRNA, the ribosomal alarmone (p)ppGpp, or bacterial toxins such as RelE which have been shown to stimulate a similar activity. Translation is required for cleavage, suggesting that the ribosome participates in the reaction in some fashion. When normal protein synthesis is compromised, A site mRNA cleavage and the tmRNA system provide a mechanism for reducing translational errors and the production of aberrant and potentially harmful polypeptides.

Bacterial Toxins↗

PubMed2003

Heat shock transcription factor 1 is involved in quality-control mechanisms in male germ cells.

Quality-control mechanisms in spermatogenesis are important to eliminate injured or abnormal cells, thereby protecting the organism from abnormal development in the next generation. The processes of spermatogenesis are highly sensitive to high temperatures; however, the mechanisms by which injured germ cells are eliminated remain unclear. Here, we found that heat shock proteins are not induced in male germ cells in response to thermal stress, although heat shock transcription factor 1 (HSF1) is activated. Using HSF1-null mice, we showed that apoptosis of pachytene spermatocytes was markedly inhibited in testes with a single exposure to heat and in the cryptorchid testes, indicating that HSF1 promotes apoptotic cell death of pachytene spermatocytes exposed to thermal stress. In marked contrast, HSF1 acts as a cell-survival factor of more immature germ cells, probably including spermatogonia, in testes exposed to high temperatures. These results demonstrate that HSF1 has two opposite roles in male germ cells independent of the activation of heat shock genes.

Animals↗

PubMed1990

Quality control of anti human CD3 and CD4 monoclonal antibodies.

By testing two monoclonal antibodies (MoAb), we tried out two methods, which might be suitable for quality control of anti human T cell MoAb. RIV6 and RIV9 were investigated by flow cytometry and Enzyme-linked Immunosorbent Assay (ELISA). The characteristics, specificity and biological activity of RIV6 and RIV 9 were determined and compared respectively with other CD4 specific MoAb, OKT4, OKT4a, LEU3a and the CD3 specific MoAb OKT3 and LEU4 by flow cytometry. An ELISA was set up to quantify mouse IgG3 antibody. Specificity, plate variability and day to day effects were determined. The results illustrate that ELISA and flow cytometry are valuable tools in the quality control of these antibodies.

Animals↗

PubMed1981

Three-pool analysis for quality control: a method for daily differentiation of analytic error from random variability.

Using the Z statistic we have devised a novel, mathematically simple concept for daily quality control of laboratory procedures. The method allows rapid identification and differentiation of systematic errors from random variability on a daily basis, increases confidence in the accuracy of reported results, reduces the number of repeat analyses, and allows the analyst to detect a deteriorating quality control pool. Using three controls instead of one or two increases the chance of detecting out-of-control situations and uses simplified statistical calculations summarized on a single graphic wall chart to monitor the daily accuracy and precision of analytic procedures. The method is adaptable to any type of specimen quantitatively analyzed and can be used in large or small laboratories with light or heavy workloads. This paper reflects what happens in a small laboratory with only one run each day, but, the system has been tested in a large community hospital with a heavy workload and multiple runs each day. Although this procedure is presented for the clinical laboratory, the method would be equally useful in industry.

Laboratories↗

PubMed1989

Statistical quality control in nursing homes: a key indicator to evaluate patient incontinence care.

The authors provide descriptive data regarding incontinence care within the framework of statistical quality control technology. Descriptive data of patient wetness frequencies were collected for 126 incontinent patients from six nursing homes in Middle Tennessee under conditions guaranteeing that they were checked and changed on a two-hour basis. One hundred inspection subsamples were randomly selected for five incontinent-patient sample sizes: 10, 15, 20, 25, and 30 patients. The average and expected variability of patient wetness frequency was calculated for each of these subsamples. These measures help nursing homes determine if they are in compliance with state and federal regulations regarding the timeliness of incontinence care. The authors suggest how nursing home management and regulatory agencies can use statistical quality control techniques.

Aged↗

PubMed2001

Data quality assurance and quality control measures in large multicenter stroke trials: the African-American Antiplatelet Stroke Prevention Study experience.

Data quality assurance and quality control are critical to the effective conduct of a clinical trial. In the present commentary, we discuss our experience in a large, multicenter stroke trial. In addition to standard data quality control techniques, we have developed novel methods to enhance the entire process. Central to our methods is the use of clinical monitors who are trained in the techniques of data monitoring.

Journal Article↗

PubMed2002

A novel quality control slide for quantitative immunohistochemistry testing.

We introduce a novel quality control technology that may improve intra- and interlaboratory immunohistochemistry (IHC) standardization. The technology involves the creation of standardized antibody targets that are attached to the same slides as the patient sample. After IHC staining, the targets turn the same color as the stained cells or tissue elements. Unlike current clinical practice, our proposed targets are neither cells nor tissue sections. To create reproducible standards that are available in unlimited supply, we use short constrained peptides as antibody targets. These peptides are attached directly to the glass slide. We show that these peptides simulate the portion of the native antigen to which the antibody binds. They are useful in detecting subtle changes in IHC staining efficacy. Moreover, the peptides do not degrade after deparaffinization or antigen retrieval treatments. This technology may be valuable in creating nationally standardized controls to quantify IHC analytical variability.

Animals↗

PubMed1991

[Good Laboratory Practice (GPL) and quality control in Dutch laboratories].

A review of the origin of GLP (Good Laboratory Practice) and ISO (International Standard Organisation) directives is followed by a number of definitions of concepts such as quality, guarantees of quality, quality systems, etc. by laboratories (NEN 2653). These requirements are discussed in the paper. Certification is one of the guarantees of quality assessment by laboratories. Certification of laboratories is carried out by STERLAB (Laboratory Accreditation Board of The Netherlands) or the CCKL (National Coordination Committee for Quality Assurance for Health Care Laboratories in The Netherlands). In addition to certification, laboratories in the Netherlands are extremely active as regards external quality control (QC). QC is carried out by the various occupational groups. The paper finally closes with a discussion of future developments regarding quality control and certification in medical and veterinary diagnostic laboratories.

Animal Welfare↗

PubMed2001

Agricultural produces: synopsis of employed quality control methods for the authentication of foods and application of chemometrics for the classification of foods according to their variety or geographical origin.

A review of quality control methods and applications of multivariate statistical techniques on the authentication and classification of agricultural products is presented. The products reported within the frame of this article were vegetables, fruits, juices, jams, wines, cereals, bakery products, oils, tea, coffee, honey, sugar-syrups, salad dressings, and gums. The perspective of multivariate statistics as a promising tool to authenticate and classify these food products according to their geographical origin or variety was demonstrated. Several representative figures and informative synoptical tables for agricultural food products were provided both for the quality control methods employed and the multivariate analyses implemented.

Cluster Analysis↗

PubMed1996

[Microscopy laboratories for the diagnosis of tuberculosis in Madagascar: quality control].

As part of the National Tuberculosis Program (NTP), a quality control of the slides (search of acido-fast-bacilli in the sputa) of the Treatment and Diagnosis Centers (TDC) forming the National Laboratory Network was carried out in 1996. 60 TDC of the 165 TDC (36%) had been controlled according to the system of double reading of the smears. The global concordance of the results in the 60 TDC is satisfactory since it was of 94%. Reliability of smears positive was of 83%. For the negative smears reliability, 14% of the TDC had a low or insufficient level. A good quality of smears was observed in 40% of the centers. The TDC that had both positive and negative reliability at 100% were 23 (38%) of which 13 had good quality of smears. Those were especially found in Antananarivo, Toliara, Fianarantsoa and Mahajanga.

Bacteriological Techniques↗

PubMed2003

[Vaccination, quality control, and vaccine production in Brazil since 1960].

The article focuses on the Brazilian government's role in implementation of immunization policies and in the emergence of a government structure involving production and quality control of immunobiologics. It examines Brazil's National Immunization Program, creation of the National Institute for Quality Control in Health, and the Program for Self-Sufficiency in Immunobiologics. It also takes a general look at the political picture that influences participating actors and at changes in Brazil's demographic and epidemiological profile.

Brazil↗

PubMed1994

[Quality control in magnetic resonance for clinical use].

This chapter summarizes requirements, rationale and main steps in the recent evolution of protocols adopted at international level for quality controls in clinical magnetic resonance imaging (MRI) and spectroscopy (MRS). An accurate assessment of instrumental performance in MRI and MRS is essential for enhancing the clinical value of these methodologies, both in terms of anatomical and physio-pathological information. In the field of MRI, a series of Concerted Actions, carried out in the frame of the medical and health research programmes of the European Economic Communities (EEC), led to the definition of standardized methodologies and to the construction of five test objects for assessing the quality of fourteen instrumental parameters, inherent to: signal uniformity and linearity; geometry; slice position and thickness; spatial resolution; signal-to-noise and contrast-to-noise ratios; T1 and T2 precision and accuracy. The first part of this paper devotes particular attention to the protocols adopted by the EEC Concerted Actions and by the National Electrical Manufacturers Association (NEMA, US), for assessing signal uniformity, geometric distortion and signal-to-noise ratio in MRI. A brief description is also given of the rationale and protocols for measuring other MRI parameters. The second part is devoted to describe eleven parameters of instrumental performance, two test objects and the measuring protocols recently proposed by the EEC Concerted Actions for quality control in single-volume localized MRS, following their validation in a series of experimental multi-centre trials.

Artifacts↗

PubMed1991

An improved phantom for quality control of laser scanner digitizers in picture archival and communications systems.

Various quality control (QC) procedures may be used to evaluate image quality for picture archival and communications (PACS) systems. A standard PACS QC protocol applied on a regular basis is desirable to ensure optimal diagnostic performance. We describe a QC phantom designed especially to test PACS systems that acquire images by digitizing x-ray films. The phantom is a sheet of x-ray film upon which a digital test pattern is printed. Multiple parameters of image quality are tested, including resolution, contrast, gray scale, geometric distortion, and noise. Individual test patterns are incorporated to detect specific artifacts of laser scanner digitizers. As part of a regular QC protocol, the phantom provides an objective measurement of change in digital image quality over time, as well as an objective means for comparison with other systems.

Lasers↗

PubMed1994

[Quality control in clinical hemorheology: preliminary study by three centers].

Clinical or pharmacological trials require reproducible laboratory tests. The aim of this work was to investigate the conditions of quality control of two laboratory tests, blood viscosity and red cell aggregation used for hemorheology trials in three centers. The results showed that viscosity measurements require 2 standards. For red cell aggregation, the control suspension standardized media (normal an pathological aggregation) showed a good intercentre reproducibility of the dissociation thresholds but a wide variability of aggregation times. Complementary studies in 5 or 6 centres are planned in order to define national standards of quality control.

Blood Viscosity↗