In order to perform diagnostics or continuous monitoring of GIS regarding partial discharges (PD) which might occur inside a GIS, the ultra-high frequency (UHF) method is generally applied. Its advantage in comparison to the electrical measurement method described in IEC 60270 is that a bulky coupling capacitance is not required. A calibration according to IEC 60270 is not possible because of physical and measurement reasons. It is possible, however, to perform a sensitivity verification, that is detailed in the technical brochure of CIGRE TB 654. The comparability of the test results between different gases and gas pressures in the typical application range is presented and evaluated by the authors. The amplitude of the artificial defect was measured by different systems, a wideband system, as typically used for monitoring systems, and another system, which is often used for on-site commissioning tests. It can be concluded that the test results are not significantly different, whether SF6 or eco-efficient gas mixtures are used in the relevant pressure range.