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PubMedDate not supplied

The long-term quality control and clinical data evaluation of individuals in AMHTS.

A new aspect of clinical data evaluation has been revealed by our recent research on the membership of AMHTS--long-term quality control (LTQC). The state of LTQC is evaluated by the distribution of mu, where mu is (mean minus micro 0) square root n minus/sigma 0, n is the number of the samples taken each day, mean is the mean of each day's samples, and sigma 0 and micro 0 are population deviation. Correction methods have been developed to obtain reasonable correction factors against the long-term analytic errors, and they have been implemented as an on-line, real-time subsystem of the AMHTS information system. The correction of LTQC errors has enabled us to observe an individual's health dynamics accurately, which allows us to pursue detection methods of diseases, such as cancer, in terms of a homeostatic disorder.

Blood Chemical Analysis↗

PubMed1990

External quality control of gamma cameras--results of an inter-laboratory comparison study in Austria.

Some 28 nuclear medicine departments out of a total of 40 participated in a nationwide Austrian interlaboratory comparison of the imaging quality of gamma cameras. The participation was voluntary, and confidentiality of the individual results was guaranteed. The survey was completed within 2 months, employing instructors to administrate the tests. An emission phantom simulating a flood field with non-uniformities was imaged by 43 cameras, and 54 images were evaluated. The test images were read by the participants using a graded rating scale to indicate the probability of the presence of a non-uniformity in the various parts of the image. The rating data were used to construct individual ROC curves for each image. The area under the ROC curve was used as the ranking parameter for image quality. The results show a spread of the ROC areas between 0.6 and 0.99, with a median of 0.81. A correlation was found between the year of installation and the ROC area obtained from the gamma camera, indicating improvements of performance in more recent cameras, which accounts for part of the variation of the ROC areas. The remaining variations are due to differences in the performance of the gamma cameras. Feedback was provided to the participants by describing individual performance with respect to the true structure of the phantom and by comparing this performance with that of the group. A questionnaire accompanying the test phantom yielded information about the practice of routine quality control and about details of the acquisition and analysis of images.(ABSTRACT TRUNCATED AT 250 WORDS)

Austria↗

PubMed1976

Stability and precision of a new ampuled quality-control system for pH and blood-gas measurements.

We describe an evaluation of the in-use stability and short-term precision of a three-level ampuled quality-control system for monitoring pH, pCO2, and pO2 measurements on clinical blood-gas analyzers. In three hospital laboratories, 324 such ampuls were opened and allowed to stand with their contents exposed to atmospheric conditions for accurately timed intervals up to 240 s. Contents were then analyzed for pH, pCO2, and pO2. Student's t-test was used to evaluate the significance of differences observed in recoveries after time exposure. At a signifcance level of P less than or equal to 0.05, the only significant changes observed throughout the first minute of exposure were average pO2 increases of 180 Pa (1.4 mmHg) (+ 1.4%) and 230 Pa (1.7 mmHg) (+ 2.9%) at levels of 13.4 and 7.7 kPa kPa (101 and 58 mmHg), respectively. The ampuled system was found to be stable precise convenient, and suitable for use in the routine laboratory.

Autoanalysis↗

PubMed2001

SIHONSCORE: a scoring system for external quality control of leukaemia/lymphoma immunophenotyping measuring all analytical phases of laboratory performance.

For the diagnosis of leukaemia and leukaemic lymphoma, clinicians frequently have to rely on the results of immunophenotyping. To improve the quality of these results, the Dutch Foundation for Immunophenotyping of Haematological Malignancies (SIHON) initiated external quality rounds in 1986. Over a period of more than 10 years, this has led to improvements in the interpretation of immunophenotyping results. However, the evaluation of results focused mainly on the correctness of the interpretation of the immunophenotypical data, leaving the preceding analytical phases unevaluated. Therefore, in 1996 SIHON developed a more comprehensive scoring system, called SIHONSCORE, covering all three phases of immunophenotyping, namely the pre-analytical (i.e. choice of the staining panels), analytical (i.e. the technical part consisting of sample preparation, data acquisition and analysis) and the post-analytical phase (i.e. the interpretation) of the laboratory process. Here, we report how SIHONSCORE was successfully applied to three consecutive external quality rounds consisting of a total of nine different cases tested. For laboratory certification, participation in external quality control programmes is required. Evidently, criteria are needed to define the minimum acceptable performance of a certified laboratory. With SIHONSCORE, a useful instrument is obtained evaluating all phases of the performance of laboratories in leukaemia and lymphoma immunophenotyping.

Clinical Laboratory Techniques↗

PubMed1999

Quality control: from molecules to organelles.

There is a vast body of literature on the quality control of protein folding and assembly into multisubunit complexes. Such control takes place everywhere in the cell. The correcting mechanisms involve cytosolic and organellar proteases; the result of such control is individual molecules with proper structure and individual complexes both with proper stoichiometry and proper structure. Obviously, the formation of organelles as such requires some additional criteria of correctness and some new mechanisms of their implementation. It is proposed in this article that the ability to carry out an integral (key) function may serve as a criterion of correct organelle assembly and that autophagy can be accepted as a mechanism eliminating the assembly mistakes.

Chloroplasts↗

PubMed2006

Urban stormwater quality control analysis with detention ponds.

This paper presents methodologies for the development of stormwater quality control measures based on the derived probability distribution approach. These stormwater control measures, such as the fraction of pollutant removed from storage facilities, are closed-form analytical models and can be effectively used to evaluate pollutant loads to receiving waters. In this study, a simple form of rainfall-runoff transformation with lumped parameters is first extended to take into account the spatial variations in model parameters. Second, the infiltration process is further incorporated to the rainfall-runoff transformation. This study demonstrates that analytical models can be developed with various levels of complexity based on different hydrologic considerations. The performance of the analytical models is evaluated in a case study, and the results indicate that, with an appropriately formulated rainfall-runoff transformation, analytical stormwater runoff models are capable of providing comparable results to continuous simulation models in the evaluation of the long-term performance of storage facilities.

Models, Theoretical↗

PubMedDate not supplied

[Rapid method of riboflavin quality control upon enrichment of prepared dishes].

The authors propose a rapid method permitting riboflavin quality control after its addition to dishes. The method involves acid hydrolysis of the product using riboflavin-binding apoprotein. The assay requires no enzymatic hydrolysis and takes 1 hour. It correlates with a routine dithionite technique (r = 0.992), which tends to overestimate the results by 24%. In view of the method efficacy it is recommended for riboflavin assay in vitamin-enriched foodstuffs.

Carrier Proteins↗

PubMedDate not supplied

Quality control in blood alcohol analysis: simultaneous quantitation and confirmation.

Using a single-injection, dual capillary column, headspace gas chromatography (HS/GC) technique, simultaneous quantitation and confirmation of routine blood alcohol analysis are described. Quality control procedures utilized in sample preparation and analysis, as well as HS/GC methodology, are delineated. A comparison is made between the results of a conventional packed column HS/GC method and the dual capillary column HS/GC method using a decomposed blood sample.

Blood Chemical Analysis↗

PubMed2005

Quality control in urinary stone analysis: results of 44 ring trials (1980-2001).

Urinary stone analysis is the most important diagnostic step after stone removal from the body. The methods employed for these analyses are based on diverse analytical principles. Chemical methods are used for detecting individual ions. Infrared spectroscopy is used for examining molecular structures, and X-ray diffraction for determination of the crystalline structure of a substance. Since 1980, a twice-yearly ring trials quality control survey has been on offer to examine the quality of urinary stone analyses. A summary of the results of 44 ring trials (1980-2001) has been compiled for individual pure substances and binary (two-component) mixtures. On average, 100 laboratories have participated in these ring trials. Initially, over 80% of the participants carried out their analyses using chemical methods. In 2001, this figure decreased to a mere 13%. In contrast, a progressive increase in the use of infrared spectroscopy was observed, up to 79% of all participants employed this method. X-Ray diffraction was only employed in a small number of specialised laboratories (5-9%). The chemical methods produced a very high proportion of errors (6.5-94%) with both the pure substances and binary mixtures, whereas high error rates for infrared spectroscopy and X-ray diffraction were confined to individual substances only. Due to the poor results in the ring trials, the majority of laboratories stopped using chemical analysis, which is now considered to be obsolete. Regarding mixtures, error rates of over 10% also occurred with infrared spectroscopy and X-ray diffraction. Ring trials are indispensable for the quality management of urinary stone analysis.

Diagnostic Errors↗

PubMed1993

[Trauma score systems as instruments in quality control. A prospective study on validation of 7 trauma score systems with 612 trauma patients].

Quality control in the treatment of trauma patients often consists in comparisons of survival rates. The trauma population under study is seldom defined with regard to severity of injury. Therefore crude survival rates are of little help when the quality of care is discussed. Trauma scores attempt to summarize the severity of injury of trauma patients in a single number. They attempt to translate differences in the severity of injury into a common language. This study tested the validity of seven common trauma score systems in the setting of Cologne in 1987. Six hundred and twelve trauma patients treated by physicians at the scene of the accident were prospectively followed up in 32 hospitals. Final diagnosis, treatment, complications, and survival were evaluated. Sensitivity and specificity in predicting survival were calculated for the following systems: Glasgow Coma Scale, Trauma Score, Revised Trauma Score, Injury Severity Score, TRISS, Prehospital Index, Polytraumaschlüssel. The average time from emergency call to arrival of the emergency physician at the scene of the accident was 6.5 min. Four hundred and one patients (65.5%) were male. One hundred and thirty-seven patients (22.4%) suffered from apnoea, 61 (10.0%) had a systolic blood pressure lower than 90 mmHg, 117 (19.1%) had had a cardiac arrest and 174 (28.4%) were unconscious. Four hundred and twenty-three patients (69.1%) left hospital alive. All trauma score systems tested showed sensitivities and specificities greater than 83%. They all proved their ability to classify trauma patients according to severity of injury. The TRISS performed best of all, with sensitivity of 93.1% and specificity of 93.7% at a cut-off point of 0.85.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed2002

Tissue microarrays: a new approach for quality control in immunohistochemistry.

AIMS: To improve the interpretation of immunohistochemistry (IHC) staining results the use of a tissue microarray technique was established in a routine setting. METHODS: A tissue microarray was constructed by harvesting 600 microm tissue cores from paraffin wax embedded samples available in a routine pathology department. The punches originating from non-tumorous tissue were placed on host paraffin wax blocks. The microarray contained 12 different tissue samples, with a wide antigen profile and a dimension of 3.5 x 3 mm. One section of the multitissue array was placed as an "internal" positive control on each slide of the patient tissue to undergo identical immunohistochemical procedures. RESULTS: Using the tissue microarray technique as a tool for internal quality control, the interpretation of immunohistochemical staining of more than 20 different antigens in routine IHC was improved. The tissue microarray did not influence the staining results in conventional IHC or in different automated IHC settings. CONCLUSION: The regular use of an institution adapted tissue microarray would be useful for internal positive control in IHC to enable different laboratory demands. Furthermore, this technique improves the evaluation of staining results in IHC.

Antigens↗

PubMed2004

HAIRVEQ: an external quality control scheme for drugs of abuse analysis in hair.

The Istituto Superiore di Sanità of Rome, Italy, in cooperation with Institut Municipal d'Investigaciò Mèdica of Barcelona, Spain, set up an external quality control program (HAIRVEQ) to evaluate reliability in hair testing for drug abuse by laboratories from the Italian National Health Service. Samples included in the program were real hair samples from drugs consumers. Prior to sending, hair samples were reduced to powdered form, mixed to ensure homogeneity and tested with GC/MS by four Reference Laboratories. Up to now, four different exercises have been concluded and 23 laboratories participated. Samples containing high and low concentrations of opiates, cocaine and metabolites, low concentrations of MDMA and two blank samples, were included in the intercomparison exercises performed in the first year of HAIRVEQ activities. Results show an insufficient performance of participating laboratories. About 82% of laboratories reported incorrect results on a qualitative basis (false positive and false negative results) for some of the submitted samples. More than one-half of laboratories reported quantitative results (60%). On the basis of the calculated z scores, only between 35 and 55% of results reported should be considered as satisfying. Guidelines have to be provided by Italian authorities for method validation as well as set of recommended cut-off concentrations to orientate laboratories in their quality objectives when developing analytical methodologies as tools to improve reliability and consequently performance of hair analysis.

Automobile Driving↗

PubMed1982

Statistical evaluation of a quality control method for isolation of pathogenic Vibrio species on selected thiosulfate-citrate-bile salts-sucrose agars.

The recovery of Vibrio cholerae, Vibrio fluvialis, Vibrio parahaemolyticus, and Vibrio vulnificus, employing eight strains of each species, was studied by using four brands of thiosulfate-citrate-bile salts-sucrose (TCBS) agar prepared according to manufacturers' instructions and following a standardized procedure. A standardized broth inoculum of each strain was placed on duplicate plates of each brand of TCBS agar and also on tryptic soy agar (Difco Laboratories) containing 1% (wt/vol) NaCl, the latter serving as the control. Plates were inoculated in a sequence designed to compensate for bias associated with multiplication of the bacteria during the inoculation procedure. Colony counts and quality of growth were recorded after incubation for 18 h at 35 degrees C. The comparison procedure was repeated four times at weekly intervals. Data were analyzed by using an analysis of variance model. The recovery and quality of growth of each species varied significantly on the different brands of TCBS agar. Significant variability was also identified for some components of the inoculation procedure. Modifications of the inoculation procedure are suggested to minimize sources of variance. A simplified statistical procedure, based on the t test, is described for media quality control for laboratories routinely isolating pathogenic Vibrio spp.

Bacteriological Techniques↗

PubMed1991

Possibilities of interventional ultrasound (IVUS) in intraoperative diagnostics and quality control in peripheral vascular surgery.

The IVUS system allows for a complete, only slightly invasive assessment of the femoral, pelvic and abdominal vessels in cross-section within the framework of intraoperative diagnostics and quality control. This method provides clear information concerning the vascular walls and internal structure. In our experience so far, it provides an ideal form of intraoperative control in cases of venous thrombectomy, embolectomy in the abdominal and pelvic vessels, following half-closed and open thromboendarterectomy and after intraoperatively performed angioplastic interventions.

Embolism↗

PubMed1992

Interpretive criteria and quality control guidelines for lomefloxacin and meropenem in susceptibility tests of Haemophilus influenzae using Haemophilus test medium.

Lomefloxacin and meropenem were tested in a multilaboratory study to establish susceptibility testing interpretive criteria and quality control (QC) guidelines for Haemophilus influenzae using Haemophilus test medium (HTM). Interpretive criteria were established by using triplicate testing of 102 representative H. influenzae strains. Only a susceptible category was proposed for lomefloxacin (greater than or equal to 22 mm and less than or equal to 2 micrograms/ml) and meropenem (greater than or equal to 13 mm and less than or equal to 4 micrograms/ml) due to the lack of resistant isolates. QC range for H. Influenzae ATCC 49247 were established using multiple HTM agar and broth base lots, three disk lots for each drug, and a number of test replicates consistent with the National Committee for Clinical Laboratory Standards M23-T guideline.

Anti-Infective Agents↗

PubMed2006

Using a quality control approach to define an 'adequately cellular' liquid-based cervical cytology specimen.

OBJECTIVE: To define a minimum acceptable total squamous cellularity for (ThinPrep) liquid-based cervical cytology (LBC) specimens using quality control techniques. METHODS: Two hundred LBC preparations were made containing varying numbers (<200) of severely dyskaryotic squamous cells and with varying total cellularities. RESULTS: Ninety-eight per cent of the LBC preparations that were missed by one or more of three cytoscreeners had fewer than 16 abnormal objects (single dyskaryotic cells or clumps of cells) and 87 dyskaryotic cells. The minimum ratio of dyskaryotic to total squamous cells that, in a preparation of 5000 squamous cells has a probability of at least 0.98 that 87 or more dyskaryotic cells will be present is 1:47. Twenty-three preparations diagnosed as abnormal had ratios of dyskaryotic to total squamous cells of between 1:2.5 and 1:4596. There is thus no feasible minimum acceptable squamous cellularity that will give an acceptable probability of detection of all specimen vials containing abnormal cells in the observed proportions. CONCLUSIONS: It is suggested that the minimum acceptable cellularity for LBC specimens is set pragmatically by the screening programme to give a feasible percentage of repeat tests.

Carcinoma, Squamous Cell↗

PubMed2002

Erythrocyte sedimentation rate: use of fresh blood for quality control.

The erythrocyte sedimentation rate (ESR) remains the most widely used laboratory test for monitoring the course of infections, inflammatory diseases, and some types of cancer. Several test methods have been developed recently, and as a result the safety and reliability of ESR testing procedures have improved. The method recommended by the International Council for Standardization in Haematology and the National Committee for Clinical Laboratory Standards for ESR measurement is based on the traditional Westergren method, using EDTA-anticoagulated samples without dilution. In clinical laboratories, reliable methods for calibration and the use of appropriate control materials are requiredfor monitoring the accuracy and precision of the routine method. We describe and evaluate a procedure for achieving the daily quality control of ESR and for establishing the limits of agreement between working and reference methods. Data from routine patient samples were used to calculate the daily cumulative mean and to monitor its reproducibility over time. Finally, to monitor analytic performance, a comparison was made between results from the measurement of ESR in specimens stored at 4 degrees C for 24 hours and results obtained in fresh samples.

Anticoagulants↗

PubMedDate not supplied

[Quality control of the diagnosis of malaria in the province of Cienfuegos, Cuba].

Data were collected by surveying all the technicians that worked at the different primary and secondary health care units. A quality control was carried out in the diagnosis of paludism in the 18 laboratories of the province of Cienfuegos. Various parameters were controlled. The method A considered 4 aspects to be evaluated: preparation of the material, sample taking, staining and microscopy. The method B consisted in an efficiency test by the observation of a set of laminae negative and positive to Plasmodium vivax and Plasmodium falciparum. In both cases, it was established a scoring scale. Besides, the physical conditions of the laboratory, the personnel permanence, as well as the time of experience in the diagnosis of paludism, were taken into account. The best results were obtained with the fixed personnel working in the paludism section. It was proved with a statistical significance level that the good category predominated for methods A and B after evaluating all the technicians. The study showed a better preparation of the personnel with less than 5 years of experience, which was related to the participation in the training course conducted at the provincial level by "Pedro Kouri" Tropical Medicine Institute 6 months before the investigation. Deficiencies were found in the conditions of the clinical and microbiology laboratories.

Clinical Laboratory Techniques↗