RESUMO
Automated differential systems can rapidly count larger numbers of cells compared with the standard manual procedure. When a fixed number of abnormal cells are interspersed randomly with a large number of normal cells, it can be shown mathematically that counting more cells increases the chances of detecting at least one abnormal cell. To test this hypothesis in a clinical setting, the authors compared 200-cell and 400-cell automated differentials obtained via the HEMATRAK Model 360 system with results of 100-cell differentials performed either manually or automatically for a group of 141 blood smears. Manual 100-cell differentials also were performed in a reference laboratory for comparison. In close agreement with theoretical expectation, both 200-cell and 400-cell differentials detected significantly more abnormal cells than did either the manual or automated 100-cell differential. Results of the latter two were not significantly different. Eighty-seven per cent of the slides that, according to the 100-cell manual differential, were without abnormal cells were found to have such cells on the 400-cell automated differential. Atypical lymphocytes and nucleated red blood cells were the abnormal cells most frequently identified.
Assuntos
Automação/normas , Hematologia/instrumentação , Humanos , Contagem de Leucócitos/instrumentação , Contagem de Leucócitos/métodos , Reconhecimento Automatizado de Padrão/instrumentaçãoRESUMO
Beginning in 1967, several committees have attempted to formulate a consensus opinion on how best to standardize the control of oral anticoagulant therapy. The three major proposals that evolved were: 1) to agree on a standard thromboplastin that would serve as a "reference thromboplastin", 2) to explore mathematical approaches for comparing the results obtained with various thromboplastins, and 3) the use of assayed plasmas that would serve as a common reference material for all thromboplastins. The advantages of reference plasmas as a common reference and their usefulness in the standardization of oral anticoagulant therapy are discussed.
Assuntos
Anticoagulantes/uso terapêutico , Plasma , Tempo de Protrombina , Padrões de Referência , Administração Oral , Anticoagulantes/administração & dosagem , Humanos , Controle de Qualidade , Tromboplastina/normasRESUMO
The ICTH/ICSH collaborative study failed to achieve its aims because each combination of plasma, thromboplastin and method was tested by too few laboratories in relation to intra and inter laboratory variation, and because the stability of the reference thromboplastin 70/178 is suspect. The evidence of the study does not support the superiority of reference thromboplastins over reference plasmas, but the concept of reference plasma was not adequately explored.
Assuntos
Tempo de Protrombina , Tromboplastina/normas , Humanos , Padrões de ReferênciaRESUMO
Data are presented to support the concept that the vitamin K-dependent coagulation factors are adsorbed onto the platelet membrane and that these make up part of the "plasma atmosphere" necessary for the aggregation of platelets by various agents. Together with evidence that other coagulation factors also are part of the plasma atmosphere, it is suggested that the aggregation reaction is part of the coagulation sequence. The immunologic approach to demonstrating constituents of the platelet membrane promises to be a highly specific technique for studying further the constituents of the platelet membrane and their reactions in hemostasis.
