A large multicenter study in China was conducted with patients with congestive HF, and the results showed that the critical value of PCT for the diagnosis of infection increased significantly with the increase of the severity of HF, and the threshold value of PCT for the diagnosis of concomitant infection in patients with grades II, III, and IV congestive HF is 0.086 μg/l, 0.0192 μg/l, and 0.657 μg/l [66]. Here, CALCA is linked to hydrops fetalis.