INS and medullary thyroid gland carcinoma: The insulin index of the MTC group (4.5 ± 0.2) was significantly higher than that of the Ficoll-400 group (3.2 ± 0.4) and 1077 group (3.5 ± 0.3) and similar to that of the HPU group (4.7 ± 0.1).