Geophysical methods based on surface waves have become very popular in recent decades due to their versatility and reduced cost of execution compared to other invasive techniques. Indeed, many seismic design codes suggest the use of these methods to estimate main parameters for seismic site classification such as Vs30. Due to space constraints in urban environments, measurements through linear arrays using active and passive techniques are usually combined to reach the exploration depth required by seismic site classification regulations. Although several good practice guidelines have been developed for performing this type of geophysical explorations [1], one of the remaining major challenges is to relate the results of these explorations to uncertainty quantifiers. For example, in the case of passive surveys, some indicators can be obtained as part of the data process from dispersion curve variability associated to the uncertainty in the direction of incidence of surface waves. In the case of active tests, there are effects associated with the filtering method used to eliminate the near and far-field effects, as well as other difficulties related to higher Rayleigh-modes [2] or heterogeneity of the site. In this paper, we study the effect of body waves unavoidably induced in active tests on the proper determination of the dispersion curve of a site. For this purpose, active tests are carried out using triaxial geophones to extract from the records the motion effectively corresponding to Rayleigh waves by means of the Normalized Inner Product technique. MASW2D tests are also performed to relate the results to the heterogeneity of the studied sites. The results show that the effects of body waves are negligible for frequencies above about 8 Hz, but below this value, in the transition zone with ESPAC passive tests, the differences can be more significant. These results are used to introduce uncertainty indicators in this type of explorations. [1] Foti, S., Hollender, F., Garofalo, F. et al. Guidelines for the good practice of surface wave analysis: a product of the Interpacific project. Bulletin of Earthquake Engineering 16, 2367–2420 (2018). [2] Tremblay, S-P & Karray, M. Practical considerations for array-based surface-wave testing methods with respect to near-field effects and shear-wave velocity profiles, Journal of Applied Geophysics, Volume 171, 103871 (2019).