Optimizing recovery of platelets in platelet rich plasma by the simplex strategy.

A Simplex is an empirical, geometric feedback strategy which progressively programs a series of experiments according to the results of the preceeding experiments. It leads to definition of conditions which maximize or minimize the result of experiments in two or more variables. When applied to study a laboratory method it dictates simultaneous variation of the conditions of an experiment, differing from the usual approach in which variables are altered sequentially and arbitrarily. A two variable Simplex (force and duration of centrifugation) has been applied to maximize platelet recovery in platelet rich plasma (PRP). The technique of Simplex is described. Maximal recovery of platelets in PRP was reached by centrifugation at 2160 X g for 2.7 minutes. To confirm the correctness of this result, platelet concentrates were prepared from PRP's separated by three different methods: 1) conditions determined by Simplex, 2) American National Red Cross recommended method (2820 X g for two minutes), and 3) Canadian Red Cross recommended method (995 X g for nine minutes). Mean recovery of 78 per cent was obtained by Simplex, significantly higher than 61 per cent with the American National Red Cross method (p greater than .005) and higher than 69 per cent with the Canadian Red Cross method. Simplex strategy is recommended as a simple, powerful technique for determining optimal experimental or laboratory conditions.