What can we expect from the CIEMAT/NIST method?

During the last years the CIEMAT/NIST (C/N) method was widely used to determine activities of different radionuclides. The impression is forced that the C/N method could be a universal method for all types of radionuclides. This paper shows under which conditions the C/N method can be used, where its limits are and which uncertainties can typically be achieved.