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PubMed1991

Multirule quality control procedures.

Multirule quality control procedures employ combinations of individual quality control rules to increase the probability of error detection without increasing the probability of false rejections to unacceptable levels. Performance characteristics of several example multirule procedures are described, and general recommendations are made for their selection and use. Multistage quality control procedures tailor the control rules employed to the frequency of errors expected during a given phase of analyzer operation. During analyzer startup, sensitive rules are employed; after acceptable analyzer performance is demonstrated, less sensitive rules are used for routine monitoring. As they tend to deteriorate quality control rule performance, between-run variations should be minimized.

Chemistry, Clinical↗
PubMed1991

A quality control method in cardiac surgical outcome: experience in 462 patients.

The aim of our study is to verify the reliability, reproductiveness and simplicity of a method to control cardiac surgical results. We divided 462 adult patients, operated on for acquired heart disease from October 1989 to January 1991, into five classes according to an individual score which was predictive for their operative mortality risk. The score resulted from 15 different risk factors tested with univariate and multivariate analysis against one event: operative death. The total number of deaths was 12: 2, 2, 1, 2, 5 for each class respectively. When comparing the predicted versus our observed mortality, we found no statistically significant difference, using the chi-squared test. The method we used is highly predictive for surgical mortality risk: it makes the results objectively comparable among different institutions; it is useful as a self-controlled quality method for cardiac surgical activity in any single institution.

Adolescent↗
PubMedDate not supplied

[The SUVA (Swiss Accident Insurance Association) statistics and quality control].

Overall quality control in medicine takes place on various levels: Physician--Hospital--Insurer--Authorities, each having different requirements. Comparative standards are rather seldom. A model for a comparative standard for insurer purposes, the medical statistics package SUMEST' is presented. This model is diagnoses oriented and includes parameters for the severity of the accident, cost of treatment and treatment outcome, all based on 5-year data pool results.

Accidents, Occupational↗
PubMed1989

[Systematic assessment of postoperative complications. A form of personal quality control].

A quality control program for the surveillance of surgical complications is described which includes all persons working at a surgical unit. The house surgeon when writing his letter for the general practitioner after the patient is demissed uses a special form for postoperative complications. Ten well defined types of complications, e.g. haematoma, fistula, abscess, pneumonia are recorded. Another surgeon responsible for the control program gathers weekly all forms presenting the results monthly at an audit to all surgeons of the unit. Here results are discussed in detail. Each surgeon gets his own complication profile monthly. Every three months the results of surveillance program are presented to all staff members including nurses, so that cooperative actions to reduce the complication rate can be taken. From January 1, 1985 to June 30, 1987, 2597 operations were performed, 213 patients (8.2%) suffered postoperative complications especially after surgery of the colon and rectum (28%), cholecystectomy (26%) and hernia repair (18%). Comparing three time periods (1985, 86, 87) no significant amelioration of complication rates were found. But factors influencing complications like very high age of patients, seriousness of the disease, and diabetes were not evenly distributed in all three samples. Therefore it might be impossible to lower the complication rate since those factors can't be influenced by better preparation for and better performing of surgery.

Germany, West↗
PubMed1979

Suitability of commercial control sera for the quality control of activity determination of alkaline phosphatase.

The suitability of thirteen commercially available control sera for measuring alkaline phosphatase (EC 3.1.3.1; orthophosphoric acid monoester phosphohydrolase, ALP) activity in human serum was tested. Apart from differences in ALP activity observed in some reconstituted commercial sera, the behaviour of control materials towards experimental variables such as the nature and concentration of the substrate, pH and type of buffer (or PO4-acceptor) together with the composition of the isoenzymes present in human serum highlights the problems and difficulties if commercial materials are to be used as control sera. The half-saturation constants in control sera were in all cases smaller than those of ALP isoenzymes from bone and liver. The shape of substrate activity curves and the pH optimum in most of control sera differed from that of human serum. The discrepant kinetic data of control materials and human serum may mask or suggest changes relevant to commercial quality control serum but not to samples of human serum.

Alkaline Phosphatase↗
PubMed1976

On the design of clinical chemistry quality-control sera.

Quality-control specimens having quantitave interspecimen relationships were prepared by (a) making admixtures of two serum pools and (b) making various dilutions of the admixtures. The specimens were analyzed for many constituents to illustrate how the data obtained could be manipulated and used. The inter-related specimens permit the reduction of quality-control data to a few target values and should be particularly useful for the evaluation of multi-channel analyzers, and for use in inter-laboratory proficiency surveys. Aspects of the design of quality control and proficiency test specimens are also discussed.

Alkaline Phosphatase↗
PubMed1992

Development of revised quality control limits for disk diffusion susceptibility tests of selected cephem antibiotics with Haemophilus influenzae and description of a new control strain.

Inconsistent quality control results in disk diffusion testing of cefaclor, cefamandole, cefonicid, and cefuroxime with Haemophilus influenzae ATCC 49247 and Haemophilus test medium (HTM) prompted a search for an alternative control strain that would provide more reliable results. A five-laboratory study was conducted to evaluate two candidate H. influenzae strains as possible alternatives to the aforementioned strain. Repetitive testing of the candidate strains and H. influenzae ATCC 49247 over several days with a total of six different lots of HTM documented consistent performance of the two candidate strains and confirmed inconsistent results for some of the antibiotics with H. influenzae ATCC 49247. In particular, certain lots of HTM failed to yield cefaclor and cefamandole zone sizes within the quality control range advocated by the National Committee for Clinical Laboratory Standards. Because of the greater consistency offered by the new strains, one was selected (now designated H. influenzae ATCC 49766) to be recommended for routine quality control testing of cefaclor, cefamandole, cefonicid, cefuroxime, and the related carbacephem loracarbef. The new control strain and zone size ranges proposed here have been approved by the National Committee for Clinical Laboratory Standards in place of the previously recommended strain and zone size limits for testing of these five cephem antibiotics.

Ampicillin↗
PubMed1986

The state of quality control: a critique.

Quality control of clinical laboratory testing must ultimately assure that test results consist of medically reliable information that is received where needed, when needed. This review shows that, despite the sophistication and complexity of current quality control procedures, numerous problems continue to prevent the achievement of this ideal. Solutions to some of these problems are suggested.

Laboratories↗
PubMed1978

Computers and quality control in nuclear medicine.

The general topic of computers and nuclear medicine quality control may be approached from two main areas; controlling the quality of computerized studies, and computer applications in general nuclear medicine quality control. Overlap occurs when quality control of computer studies is performed by the computer itself. The uses of computers in record-keeping and in quality control of imaging instrumentation and in vitro studies, including radioimmunoassay, are discussed in this review. Aspects of quality control for computerized clinical cardiovascular, cerebral, and renal studies and emission computed tomography are reviewed, including consideration of difficulties and inaccuracies involved in the studies. Any automatic computer analysis program should incorporate adequate checks and error detection protocols and should illustrate results for verification. Current routine quality control procedures using the computer unfortunately are few. Quality control criteria are needed for camera/computer systems in high count rate clinical applications, and increasing emphasis should be aimed at quality control of those computerized dynamic and function studies in current clinical use. The computer has a valuable potential for nuclear medicine quality control. In vitro and computerized in vivo studies can be analyzed by readily available statistical programs, and variances can be monitored continuously. Computers can calibrate and monitor instrument performance regularly, and can handle managerial and clerical duties such as bookkeeping.

Cardiovascular Diseases↗
PubMed1988

Multiprogram characterization of laboratory bias, precision, and total error. Proposal for improved assessment with shared external and expanded internal (regional) quality control pools.

We establish that, for the analytes aspartate aminotransferase, glucose, phosphorus, and potassium, there is significant correlation between laboratory performance as determined by College of American Pathologists-sponsored external (Surveys) and expanded internal (regional) quality control (Quality Assurance Service) programs. However, relatively low parametric and nonparametric correlation coefficients and significant departure of linear regression slopes from unity reflect major differences in the calculated parameters of absolute bias, precision, and total error obtained through internal and external quality control. Significantly better performance in both Surveys and the Quality Assurance Service was documented for laboratories participating in the College of American Pathologists Laboratory Accreditation Program. Multiple descriptors of laboratory quality, as indicated here, are superior in describing laboratory performance to proficiency testing alone. As a bridge between external and internal quality control, shared pools of quality control materials are described for use as unknown Survey challenges and subsequent distribution for regional quality control. Such programs, which can be configured to serve thousands of laboratories, could offer cost savings, better quality assurance, and improved characterization of laboratory performance by minimizing interprogram differences in control matrix and method classification and providing greater reliability of target values.

Academies and Institutes↗
PubMed1991

A quality-control program for colposcopic practice.

Quality control is accepted as an integral part of the cytology laboratory's activities. However, provision of similar safeguards for colposcopic practice in assessing patients with abnormal cervical cytology has been an elusive problem. This report describes the quality-control program for colposcopy that is used province-wide in British Columbia for 21 hospital-based clinics staffed by 35 colposcopists. Copies of the results of all colposcopic examinations performed are sent to the Central Cytology Laboratory where the program is coordinated and the data are collated, analyzed, and evaluated. These data are used to set standards against which each colposcopist's performance and activity can be measured. One of the quality-control indicators used is a comparison between the colposcopic impression of the lesion and the corresponding direct biopsy diagnosis. Correlation within one histologic degree occurred in 86% of patients examined; this information was used to set a performance standard of 80% as the quality-control index for this particular indicator. Three colposcopists had scores below this standard. Comparisons were also made between presenting cytology, directed biopsy results, initial colposcopic impression, and final colposcopic evaluation (the clinical working diagnosis). The other major aspect of the quality-control program consists of an analysis of all cases of diagnosed invasive cervical cancer in the province in a given year to determine whether any colposcopically related errors occurred in the investigation and management of these cases. This system helps to identify individuals who may benefit from additional training.

Biopsy↗
PubMed1986

Quality control in cytopathology.

Quality control in cytopathology involves specimen collection, preparation, screening, and final diagnosis. The measures to assure the optimal performance and to detect the malfunctions in these areas are discussed. Careful selection and application of proper procedures, proper training and continuing education of cytotechnologists and pathologists, and reasonable workload for screening cytotechnologists and important factors in quality assurance.

Pathology, Clinical↗
PubMed1979

Accuracy in interlaboratory quality control programs.

Interlaboratory quality control programs provide an important contribution to achieving and maintaining accuracy in clinical laboratories. The various strategies for providing accurate target values in the two principal types of interlaboratory programs are reviewed.

Laboratories↗
PubMed1976

Regional quality control.

Methods of quality control of some major haematological techniques are described. These methods have been applied in haematology laboratories serving a population of 2 million using existing facilities for preparation and transport of the necessary materials.

Blood Cell Count↗
PubMed1987

CT quality control.

A daily quality control (QC) protocol for a GE 9800 computed tomography (CT) scanner is described which quantitatively assesses system noise, an index of high contrast resolution, and the reproducibility of CT numbers for four phantom materials. The mean values and variation for each QC parameter under normal operating conditions have been determined, and their use in assessing CT scanner performance is discussed.

Quality Control↗