(a)
(b)
(c)
(d)
Figure 2: Schematic representation of OPG structural domains as compared to the standards of the available ELISA kits. (a) OPG structural domains; (b) R&D Duoset ELISA standard; (c) BioVendor ELISA standard; (d) Biomedica ELISA standard. ELISA is for enzyme-linked immunosorbent assays; OPG is for osteoprotegerin.