Using ELISA, Brandt et al. reported that the plasma MSTN level was 4–5 ng/mL in healthy subjects as well as in patients with DM [18], whereas Han et al. showed that two kits from different venders gave largely different values (32.5 μg/mL and 9.28 ng/mL when the sample from a healthy subject was measured) [15] [17]. Here, MSTN is linked to diabetes mellitus.