Since 1987, the CEA's Committee for the Establishment of Analysis Methods (CETAMA) has regularly implemented interlaboratory comparisons, entitled Evaluation of the Quality Results of Analysis in the Nuclear Industry (EQRAIN). Notably, the EQRAIN U and EQRAIN Pu interlaboratory comparisons assess proficiency in measuring a mass content of uranium or plutonium in reference solutions. This presentation deals with the results of measurement uncertainty assessments from EQRAIN U and EQRAIN Pu comparisons over 20 years of exercises (1997 2016). The mathematical approach developed allows to estimate the impact of short-term systematic and random errors to the overall uncertainty of each analytical method used in the interlaboratory comparison program. This statistical analysis shows a good consistency between measurement uncertainty values from EQRAINs and the measurement uncertainty target values established by the International Atomic Energy Agency (IAEA) for nuclear material balances (ITVs-2010).