LIANG PIN, ZHOU TONG-HUI (D. T. -W. CHOW)(Laboratory of Analytical Chemistry, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking)

A simpler and reasonably accurate method for computing the median lethal dose (LD₅₀ is described. The computing process is much simpler than Reed-Muench's method, and the accuracy attainable is precisely the same as that of Kaerber's method. By using this method, one can easily obtain the regression equation correlating the log-dose and the "probit" unit, and thereby compute the dosage for any "percentage kill", without the necessity of repeated correction. The method is also free from subjective influence. The formulae are: logLD₅₀=X_m-i(∑_p-0.5) SE₅₀=i×((∑_p-∑+(p²))/(n-1))~(1/2) b=(Y_h-Y_t)/(i(N-H)) log LD_K=log LD₅₀-(5-Y_K)/b SE_K=((SE₅₀)²+2/(nH(N-H))((5-Y_K)/b²i)²)^1/2.