An experimental test of several equivalence relations for effective resonance integrals is obtained from measurements of U238 resonance escape probability for lattices of the TRX critical facility, and measurements of the U238 resonance integrals of isolated rods of UO2 and uranium metal. The TRX lattices were H2O-moderated and composed of cylindrical, aluminum-clad fuel rods of slightly enriched uranium metal or UO2. The measurements are in agreement with two forms of equivalence among lattice and isolated rod resonance integrals for a given fuel composition. The equivalence between resonance integrals for fuel rods of different compositions (IT and UO2) does not appear to be as good.