Diagrammatic representation of binding of MoAbs binding to the two PS species present in the plasma of a normal subject, the propositus, and the propositus' son (deduced from the subject genotype). The figure shows PS domains significant for MoAb binding. The EGF domains are symbolized by a circle with a diagonal slash, and the amino acid at position 460 (P, Pro; S, Ser) is indicated by an uppercase letter. The MoAb recognizing EGF1 (HPS 54) is represented by a half-shaded symbol, and the MoAb containing Ser at position 460 (S12) of its epitope is in black. PS concentrations (percentage of the value for a normal pool) observed with the routine assay and two MoAb-based assays.§