The Estimation of Blood Platelet Survival II. The Multiple Hit Model

Summary It this paper are developed 4 models for estimation of blood platelet survival. They are put forward not as completely realistic but as at least first order approximations which should at once provide a systematic basis for estimation of mean platelet survival and the standard error of the estimate ; they will at the same time circumvent the subjective element in analysing the data with the attendant biases, and also provide a unifying theory for the several different models which the various investigators have more or less explicitly used in the past. The models may perhaps be thought of as smoothing functions to iron out the high experimental error inherent in the study of platelet survival. An attempt has been made to construct the model on the basis of present knowledge of the economy of the platelet and the factors influencing its survival. Doubtless further knowledge in these fields will call for modification of the details. Nevertheless it is evident that with these relatively simple models it is possible to generate quite a wide range of patterns which appear to conform well to those found by those working on this subject.