SERPIND1 and polycystic ovary syndrome: Complement C3 (C3) was higher in PCOS (71,028 ± 25,536 vs. 63,896 ± 26,822 RFU of C3, p = 0.037, PCOS vs. control), as was heparin cofactor II (HCFII) (4156 ± 773 vs. 3821 ± 618 RFU of HCFII, p = 0.0004, PCOS vs. control) (Figure 3 and Supplementary Table S1).