Most of the programmes for the evaluation of radio in vitro tests proceed from the anticipation that the best method should give an approximation of standard values by a curve as perfect as possible. According to our experiences this demand, however, is not decisive for a good standard curve, as in principle all standard values can be incorrect. The application of relatively simple linearising transformations and an additional curve (recovery of a normal serum) guarantees the necessary precision in the programme described. After a short description of the contents of the system, the programme for the assessment of CPBA - methods is shown, by help of which the sample changer - calculator-system determines the absolute concentration of the substance to be measured. This makes the starting point for the more complex RIA programme which methodologically takes into consideration the special problems of these tests.