At present, the optimal target after replacement for the FX levels in patients with primary amyloidosis is not known; however, it can be derived from that of patients with congenital FX deficiency: 10 to 15 IU/dL for minor bleeding and >50 IU/dL for major bleeding, trauma, or surgery.8 Physician needs to exert extra caution for volume overload particularly in AL amyloid patients with cardiac involvement when a large volume of factor replacement is used. Here, F10 is linked to AL amyloidosis.