Representative binding isotherms for the titration of PF4 with defined chain length heparins. (Upper) Raw titration data and (lower) integrated heats as a function of the molar ratio of heparin/PF4 for (A) UFH, (B) LMWH, (C) HO16, (D) HO08, (E) HO06, and (F) fondaparinux.