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PubMed1978

Use of a programmable desk-top calculator for the statistical quality control of radioimmunoassays.

We have developed an interactive statistical quality-control system for the small- to medium-sized radioimmunoassay laboratory, which can be used in a programmable desk-top calculator instead of the medium- or large-scale computer systems usually required. The design of this quality-control system is modeled after the suggestions of Rodbard and has three components. The first component evaluates the relationship between the measured response variable of the radioimmunoassay and the precision (or variance) of these measurements. This derived relationship is then used in the second component of the system as the basis for the weighting function used to calculate an interative, weighted, least squares regression of the logit-log transformation of the dose-response curve. The third component uses the quality-control parameters statistically calculated from the linearized dose-response curve to monitor whether the assay is "in-control". The calculator tabulates the means and confidence limits for the various parameters and can plot the statistical quality-control charts. The major benefit of this statistical quality-control system is that it allows the real-time computation and plotting of quality-control data with a programmable desk-top calculator.

Computers↗
PubMedDate not supplied

[Quality control in parasitology].

A quality control in parasitology has been organized since 1977, under the direction of the Exotic Pathology Society. In 1978, more than 1 200 voluntary laboratories were participating. In 1979, according to the law of the eleventh of July 1975, this control is going to be obligatory for the 3 750 public or private laboratories effecting parasitologic tests. That should improve the quality of these tests, outside any repressive aspect.

France↗
PubMed1979

An evaluation of two methods of laboratory quality control.

Two methods for quality control of automated blood counters have been compared: (1) monitoring results from patients' samples, and (2) analysis of results of a stable whole-blood control. The latter method proved better able to distinguish calibration changes from patient variation.

Erythrocyte Indices↗
PubMed1975

Quality control in diagnostic virology.

Quality control in diagnostic virology is in its infancy and some preliminary investigations are reported. Simulated specimens containing viruses have been prepared and distributed so that they could be included in the routine work of virus isolation in participating laboratories. Sera containing antibodies to rubella and influenza virus have also been sent to laboratories for testing. Laboratories were able to check their results immediately after the closing date, and could compare their performance with that of other laboratories when the analysis of each distribution was circulated. The results so far show considerable variation in performance and indicate that there is room for improvement in some laboratories. There is no evidence to show whether the exercise has had any effect on the practice of virology in participating laboratories but some baselines have been produced for comparison with the results of investigations in the future.

Antibodies, Viral↗
PubMed1976

Standards and quality control: problems and pitfalls.

The proliferation of standards and quality assurance programs is posing a major problem for mental health administrators. The authors review some of these problems and emphasize the differences between cost and quality controls. They propose that quality controls be judged on their ability to improve patient care and suggest that administrators consider the establishment of quality control offices.

Accreditation↗
PubMed1979

A quality control program to evaluate accuracy and precision of clinical chemistry determinations.

An external quality control program is described which, apart from documenting the routine performance of clinical chemistry laboratories with respect to accuracy and precision, also indicates the control efficiency of intra-laboratory quality control procedures. Participants are supplied with a large lot of stable control serum to be used in their intra-laboratory quality control program during a prolonged period of time. The statistical analysis of the submitted data consists of an analysis of variance scheme in order to separate systematic from random errors. The systematic laboratory errors are thereafter graded according to a scoring system independent of the standard deviation. The control efficiency of intra-laboratory quality control procedures is derived from a modified version of the measurability and controllability rules of Van der Grinten (1968) Stat. Neerl. 22, 43--63). Application of these rules in clinical chemistry laboratories is a first step towards a dynamic system of process deviation control. Merits of such an approach are discussed. Principles of the analysis of variance technique are dealt with. A graphical procedure to display its results is shown. Testing procedures to justify application of the analysis of variance technique are discussed and several features are illustrated.

Analysis of Variance↗
PubMed1976

Quality control and the community physician in England: an American perspective.

The quality of health care is becoming an issue of increasing public importance in both England and the United States. As the government role in providing health care grows and citizen demands increase, the effective and efficient use of health care resources and their equitable distribution become crucial. Although government responsibilities, particulary for health care, differ in both countries, as do traditions of quality control, cross-national comparisons are nonetheless useful. An examination of the role of the new English community medicine specialist and his potential for quality control may indicate what tools and powers should be introduced into a health planning and quality control system in the United State. The study concludes that at the district level of the National Health Service, where the basic planning, monitoring, and evaluation of services are to take place, the District Community Physician has very limited tools to carry out his quality control function. Although he has formal position in the unified decision-making structure, it is unlikely that he will be able to effect any substantial reallocation of resource without the voluntary support and copperation of the consultants, general practitioners, and other health providers.

Community Medicine↗
PubMed1976

The preparation of simulated water samples for the purpose of bacteriological quality control.

As part of the bacteriological quality control programme of the Public Health Laboratory Service, we were asked to investigate the possibility of providing simulated water samples for distribution to the laboratories. For this purpose it was necessary to find some means whereby suspensions of coliform organisms and Escherichia coli could be kept relatively stable in number at room temperature for a period of 7-10 days. This, it was finally found, was best achieved by adding selected strains of the organisms to improved formate lactose glutamate medium (Gray, 1964) without the lactose but with added boric acid to a final concentration of 1-8%. The procedures adopted in the successful quality control programme are described.

Boric Acids↗
PubMed1976

[Laboratory standardization and quality control in anticoagulant therapy].

Standardisation and quality control are now available for the laboratory tests which are needed to control the blood levels of anticoagulants. The most important cause for variation in results between different laboratories is the use of different types of thromboplastin. The British standards are based on the use of a national reagent with a national system of reporting supported by quality control with lyophilised plasma and thromboplastin preparations. It offers a model which has been adopted at Tygerberg Hospital, and could be used to standardise anticoagulant therapy in this country. Human brain thromboplastin is preferred to the commercially available rabbit preparations. For the first time, as far as we know, a phenol-saline extract of baboon brain thromboplastin was examined. Preliminary results indicate that it compares well with human brain extracts.

Animals↗
PubMed1975

A proposed blind routine quality control system for multichannel analyzers.

A blind quality control system using a special type of commercial reference serum is described. As packaged, the product contains six pools of analyzed reference sera with vials identified by coded numbers. The test constituents in the pools cover the range of multichannel analyzers in a random manner, i.e., each pool contains constituents in the low, normal and elevated ranges. As specific pools are not identified, and the analyst is unaware of the expected values for each constituent, results collected for quality control purposes are unbiased, i.e., free of conscious or unconscious editing. Data analysis in the proposed system is by least-squares technics. During an eight-week period, performance was studied using the standard error of the estimate to evaluate precision and the slope of the regression line to evaluate accuracy on the SMA and Mark X instruments. As an empirical comparison, the data are expressed as relative errors and precision and accuracy of analyzer performance evaluated as mean and standard deviation. The proposed regression analysis-based technic has the advantage of simultaneously evaluating linearity, as well as checking accuracy and precision over the total dynamic range of the instrument by use of a series of related serum pools.

Alkaline Phosphatase↗
PubMed1976

[Quality control of coagulation tests (author's transl)].

The results of quality control of coagulation tests from intralaboratory control programmes are reported and compared with interlaboratory surveys. The test programme includes the following assays: the thromboplastin time (Quick), the partial thromboplastin time and the thrombotest. It can be seen from the results of the thromboplastin time that reliable figures were obtained from intralaboratory quality control examinations only (CV=7% to 13%). In comparison to these results great differences were found in interlaboratory surveys (CV=15% to 30%). The result of interlaboratory surveys of the thrombotest demonstrated a CV of 15% to 20%. The intralaboratory quality control of the partial thromboplastin time showed satisfactory reliability (CV=7.4%). Satisfactory conformity of results was obtained between different laboratories only by using common reagents (CV=8.7%). Possible factors responsible for deviations in laboratory examinations are discussed and proposals for improvement in the realibility of coagulation tests are made.

Blood Coagulation Tests↗
PubMed1977

A computerized approach to statistical quality control for radioimmunoassays in the clinical chemistry laboratory.

Methods for statistical quality control for the clinical laboratory in general, and radioimmunoassay in particular, have been proposed for many years. Unfortunately, only a very small number of laboratories have adapted these procedures. By use of teletypes and other remote terminals, it is possible for all laboratories to access centralized computers where a general purpose quality control program can be stored. This relieves each laboratory of the costly task of developing software, provides some degree of inter-laboratory standardization and facilitates comparison of precision and accuracy between laboratories. A prototype program for this purpose is described. This program evaluates within-assay and between-assay variability, by means of an analysis of variance for a one-way classification random-effects model, and can monitor any assay parameter by use of control chart techniques. In addition, several tests are provided to evaluate the temporal stability of the assay system, and appropriate tests for outliers are included. Also, methods are described for combination of information from several quality control samples. This provides a valid basis for adjustment of assay results or for outright rejection of an assay. For convenience, this program is designed for output on a teletype or similar terminal located in the laboratory. Simplified versions of this program can be readily adapted to desk-top calculators. The original purpose for developing this system was to provide the clinical laboratory with a simple, general, and flexible method for assessing the performance of radioimmunoassays, but its usefulness should extend to virtually all assay methods.

Computers↗
PubMed1976

Ornithine carbamoyl transferase activity. Use of a bovine liver extract in quality control.

To obtain a pure ornithine carbamoyltransferase for quality control in clinical chemistry, the authors compared human plasma and bovine liver ornithine carbamoyltransferase. The data show that the KM of both enzymes are similar (respectively 1.03 and 1.33 mmol when ornithine is used as substrate; 1.02 and 1.06 mmol with carbamyl phosphate). The following properties are shown to be equivalent: linearity of the enzymatic reaction, inhibition by higher substrate concentrations, and temperature denaturation. The similarities between the two enzymes indicate that bovine liver ornithine carbamoyltransferase can be used in clinical chemistry quality control.

Animals↗
PubMed1978

Internal quality control of radioimmunoassays.

A modified cumulative sum technique has been applied to radioimmunoassay quality control data. The method is approximately 50% more efficient in detecting systematic changes in the mean and variance of quality control values for plasma samples than more widely used conventional methods. The salient features of the technique have been restricted to changes in the mean quality control value of a plasma pool, but potential applications to changes in variance and as a diagnostic aid to problems in radioimmunoassay have been evaluated. The method is independent of computing facilities and statistical expertise since all computations have been presented in the form of a nomogram and thus can be used by technicians at the bench.

Estradiol↗
PubMedDate not supplied

Mouse tumour tests for quality control of C. parvum preparations.

Description of two mouse tumor tests selected to control the quality of C. parvum pilot productions: transplanted Ehrlich's ascitic tumor in inbred Swiss mice and transplanted YC8 ascitic tumor in isogenic Balb/c mice. The results obtained during three years of control are analyzed, particularly accuracy, long range adequacy and reproducibility of tumor challenges and C, parvum stimulations. The effects of some parameters of the tumor tests, e.g. dose-responses, treatment schedules, tumor-host relationships and standard preparations are discussed.

Animals↗
PubMed1976

Quality control in clinical chemistry: the essential steps.

Assurance of the quality or reliability of test results is the responsibility of the laboratory and the concern of the veterinarian who uses these results in the diagnosis or treatment of animal patients. Quality assurance can be produced only by implementation and continuing maintenance of a quality control program to monitor the daily performance of the laboratory. Quality control programs usually are multifaceted and may be comprised of one or several optional components. An essential ingredient in any program designed to provide quality assurance is the "quality-awareness" of those who perform the tests or make clinical use of the test results.

Blood Urea Nitrogen↗