A STATISTICAL APPROACH FOR ANALYZING CLONOGENIC SURVIVAL-DATA

The assay of colony-forming efficiency is a mainstay in the measuremen t of cell response in vitro to many physical and chemical agents. Curr ently, data on colony-forming efficiency can be calculated in a variet y of ways. Authors rarely describe in detail the methods used to deter mine the extent of biological variation within experiments. The use of standard methods of data analysis and presentation would improve inte rpretation of data and facilitate comparison between laboratories. Her e we propose such a method. Binomial and Poisson probability theory we re used to increase the accuracy of the estimate of the surviving frac tion and to create an objective criterion for determining whether data obtained from serial dilutions of cell numbers used in the assay of c olony-forming efficiency should be excluded or included for further an alysis. The variability inherent in the calculation of surviving fract ion was determined by using Fieller's theorem, a special statistical a pplication for assessing ratios of estimates, to determine the 95% con fidence interval. All calculations were done on a simple and commercia lly available spreadsheet program. (C) 1996 by Radiation Research Soci ety