When qualifying prototype samples in terms of vibration response and dynamic characteristics, an accredited laboratory is required to implement monitoring procedures to assure the validity of the test results. According to ISO17025, such monitoring may include inter-laboratory comparison or proficiency testing.This paper presents a mechanical structure which has been designed specifically to be used as a generic reference sample during such a comparative study in which resonant frequencies of a structure need to be quantified. This paper elaborates on the analysis and design issues, which encompass theoretical analysis, both purely mathematical and by FEM (Finite Element Modeling). In addition, to allow statistical analysis of test data resulting from measurements performed by different test laboratories, the uncertainty budget  of the reference value of this sample is determined.As a first step towards a European project, a limited group of accredited test laboratories in Belgium have participated in a first Round Robin proficiency analysis. The results and interpretation of this exercise conclude this paper.