ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01517.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: All analytical methods can be defined in terms of their practicability and reliability performance characteristics. Desirable standards of performance, or analytical goals, are required for these, particularly for imprecision and inaccuracy. Goals for imprecision have been set using a variety of methods including reference values, opinions of clinicians, views of individuals, and data on biological variation. The last approach is currently favoured; desirable imprecision is equal to or less than one‐half of the biological within‐subject variation. If this goal is met, total variability of test results is increased by less than about 10% due to analytical variability. Valid estimates of within‐subject variability are available for the complete blood count. The goal for inaccuracy is that methods should have no bias so that results are comparable over time and geography; goals based on biological variation should be viewed and used, therefore, as goals for total error. In current practice, some of the goals cannot be met; they should be considered as targets worthy of achievement, not as inflexible criteria of acceptance or rejection of

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01518.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: The three main aspects of analytical quality are ‘goals for analytical qualtity’, ‘creation of analytical quality’, and ‘control of analytical quality’. In the NORDKEM‐project ‘medical need for quality specifications within laboratory medicine’ the aspects of analytical quality are combined. The aims is to make an appraisal of the different approaches to goal setting, and to develop a practical procedure for assessing analytical quality requirements. The goals are used to define which demands should be met by the process of establishing and maintaining the quality, and for design of internal as well as external quality assurance procedures. The project is an umbrella project with three main subprojects and several satellite projects. In this presentation a model for evaluation of influence of analytical bias and imprecision on the outcome from a diagnostic classification based on biomodal distri

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01519.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: Scientific principles of standardization were first applied in haematology in 1963 when the International Committee for Standardization in Haematology was established with a primary objective to improve the measurement of haemoglobin. Subsequently, ICSH has established Expert Panels on a wide range of haemat‐ological topics, including especially a Panel on Cytometry. The purpose of haematological standardization is to obtain precision, accuracy, specificity and harmonization of results between different laboratories in all countries and also between different instruments or methods in the same laboratory. To achieve these objectives ICSH sponsors collaborative studies by scientists from academic centres and from industry and uses a consensus procedure for establishing standards on the basis of the scientific data, followed by an educational programme to ensure that the standards are adopted worldwide.ICSH defines material standards and standardized methods. Material standards are classified as primary international standards, certified reference materials, secondary standards and calibrators. These must be distinguished from control preparations which are intended exclusively for quality control.Standardization of methods must also be considered at four levels: definitive, reference, selected and routine. Each has a place in practice but their roles must be clearly defined. ICSH has an established protocol for evaluation of automated blood cell counters. This defines the levels of precision and accuracy of instrument performance. It is also necessary to assess “clinical utility”. The main requirement of the practising haematologist is clinical reliability and harmonization of results for comparability. One of the major functions of ICSH is to provide an interface for collaboration between the manufacturers who develop the instruments and the users in order to achieve th

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01520.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: An approach is described for selecting QC procedures based on goals for analytical quality, the performance characteristics of the measurement procedure (imprecision, bias, frequency of errors), and the performance characteristics of the control procedure (probabilities for error detection and false rejection). Performance characteristics of stable sample QC procedures and patient data QC procedures (retained patient specimens, Bull's single‐rule algorithm, Bull's multi‐rule algorithm) are compared to determine when to apply these different QC procedures to multichannel hematology ! analysers. Precise, stable methods may be controlled using Bull's single‐rule algorithm; less precise, less stable methods require Bull's multi‐rule algorithm, retained patient specimens, or stable sample QC procedures; imprecise and unstable methods are best controlled using stable sample QC procedures. “Multi‐stage” designs may employ stable samples for “startup” testing, retained patient specimens for short term monitoring, and Bull's single‐rule algorithm for

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01521.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: External quality assessment and internal quality control in hematology is complicated by the lack of good control materials. Commercial materials do not always behave as patient blood and they are expensive. Patient specimens are unstable, but may be used either within certain time limits or as in Bull's moving average for red cell indicies.We have used retained patient specimens for internal quality control supplemented by a commercial control material. Three patient‐specimens were run alternatively on a Technicon HI and a Coulter 880 at regular intervals. The variations for each instrument and between instrument were computed. We used the 2of32scontrol rule.Our conclusion is that the Coulter 880 had an overall better performance than the Technicon H1 when using retained patient specimens. But both instruments practically met suggested analytical go

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01522.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: A supplement to a bibliography (Scand J Clin Lab Invest 1987;47 suppl. 187:1–96) dealing with quality assurance in the clinical laboratory is presented. The increasing role of national and international standardizing bodies is stressed as well as implementation of rules of “good laboratory practice”. Objectively established quality goals for all services is highly needed in order to provide a rationale for the efforts dedicated to quality improvements. Quality goals for many clinical chemistry and haematology investigations are now av

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01523.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A comparison of the differential white blood cell count using the Technicon H1, the Tech‐nicon H6000 and the Coulter VCSAbstract: One hundred blood samples were analysed on Technicon HI, Technicon H6000, and Coulter VCS hematology analysers, and the white cell differential counts were compared. All three instruments showed very good agreement for neutrophiles and lymphocytes, good agreement for eosinophiles, and acceptable agreement for monocytes. For the material analysed there were no disparities of clinical significance between the results obtained from the three instruments. Eur J Haematol 1990: 45 suppl. 53: 37

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01524.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: There was good agreement between results obtained with Coulter VCS/Technicon HI and manual counting with respect to neutrophils and eosinophils. Coulter VCS overestimates the lymphocyte percentage compared to manual counting and to HI. If, however, the percentage of so called “naked” cells are added to the percentage of manually counted lymphocytes, the agreement between VCS and the manual method is improved. The alarms given by the two instruments are of little value in detecting left shift or nucleated red blood

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01525.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract: An external quality assessment scheme (EQAS) of automated differential counts of leukocytes has been carried out using selected fresh blood specimens. The measurements were carried out one day after blood drawing because of the delay in the mail. Reference laboratories established target values for differential counts. They counted visually 600–700 cells in each specimen on smears. The concensus value among 12 laboratories for manual count of total leukocytes was used as target value, but was found on average 9% smaller than the average instrumental value. H1 results compared favorable with the target value for the differentials. The less advantageous findings on Coulter S + IV are partly explained by the age of the specimen when measured. The data indicated that better calibration of the instruments could decrease the overall variation of platelets counts and haemoglobin determinations. An EQAS involving measurement on fresh specimens is in progr

ISSN:0902-4441    

DOI:10.1111/j.1600-0609.1990.tb01526.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY