Best HUS marker since it is not an APR

• A. Hemopexin
• B. CRP
• C. Ferritin
• D. Albumin

Answer: (A)

Hemopexin is the best marker here because it reflects the heme scavenging system involved in intravascular hemolysis, which occurs in HUS, and it is not a typical acute-phase reactant driven by inflammation. In HUS, free heme released from destroyed red cells is bound by hemopexin; as this process consumes the protein, its level drops, providing a signal of hemolysis-related heme burden. In contrast, CRP and ferritin are classic positive acute-phase proteins that rise with inflammation, and albumin is a negative acute-phase protein that falls during inflammation. These inflammatory changes can mask or confound interpretation for hemolysis-specific processes, making them less ideal for indicating HUS activity.