If you're concerned about iodine, the best bet is to run a urine iodine test. Serum iodine may not be the most accurate way to assess for iodine levels in our patients. There are a number of labs that run these tests:
ZRT does dried urine iodine: https://www.zrtlab.com/test-specialties/iodine
Doctor's Data does urine iodine: https://www.doctorsdata.com/urine-iodine