Do the supplements skew lab work? Especially ones run for kidney function?

They shouldn't but depending on how hard your body is working, they could. For example, the kidneys are main detoxifying organs. They are working hard right now, but if you're eliminating correctly and eating well, the bowels, kidneys, and liver all share the burden. It’s best to wait to do evaluatory (not totally necessary) lab work until after reseeding. Excess acid might be being processed by the kidneys.