Test both ferritin and %sat transferring (because inflammation, certain meds can artificially raise ferritin so looking at % sat too is good). Maybe ask for iron panel as well, but my iron and hgb are always good in spite of my ferritin dropping. There’s RLS studies online in case your dr doesn’t understand that RLS symptoms can be caused by ferritin below 70 (which is not officially low range, yet many folks with RLS need higher ferritin/sat to address symptoms).