Abstract
When the ^<131>I-T_3 Resin Sponge Uptake test as in vitro thyroid function test is performed, it may happen that a radioiodine in blood serum due to preadministration of Na ^<131>I for thyroid uptake test is absorbed into the resin sponge. In this case, the influence that this Na ^<131>I affectes the resin sponge uptake was investigated and the corrective equation was deduced below ; U_c={C_<rI>/C_<iI>-C_s-C_s/1.1 (C_<iI>-C_s)}×100 (%) U_e : corrected resin sponge uptake C_<iI> : initial counts of ^<131>I-T_3 and Na ^<131>I in testtube C_<rI> : residual counts in resin sponge after washed C_s : counts of Na ^<131>I in blood serum 1ml
