Increased intravascular hemolysis is indicated by a decrease in which of the following?

Increased intravascular hemolysis is indicated by a decrease in which of the following?

• A. Haptoglobin
• B. Methemoglobin
• C. Methemalbumin
• D. Hemopexin

Answer: (A)

Haptoglobin is the first-line scavenger of free hemoglobin in the plasma. When intravascular hemolysis occurs, large amounts of hemoglobin spill into the bloodstream. Haptoglobin binds this free hemoglobin to form stable haptoglobin–hemoglobin complexes that are cleared by the liver. This binding capacity is limited, so as hemolysis continues, the circulating haptoglobin becomes exhausted, leading to a decreased haptoglobin level. That drop is a hallmark of intravascular destruction. The other substances aren’t as reliable indicators in this context. Methemoglobin is an oxidized form of hemoglobin; its levels don’t specifically reflect hemolysis. Methemalbumin can form during hemolysis but is not the standard marker used to indicate intravascular destruction. Hemopexin binds free heme and can also be depleted in significant hemolysis, but the classic, most direct clue clinicians look for is the fall in haptoglobin due to its consumption by binding free hemoglobin.

Haptoglobin is the first-line scavenger of free hemoglobin in the plasma. When intravascular hemolysis occurs, large amounts of hemoglobin spill into the bloodstream. Haptoglobin binds this free hemoglobin to form stable haptoglobin–hemoglobin complexes that are cleared by the liver. This binding capacity is limited, so as hemolysis continues, the circulating haptoglobin becomes exhausted, leading to a decreased haptoglobin level. That drop is a hallmark of intravascular destruction.

The other substances aren’t as reliable indicators in this context. Methemoglobin is an oxidized form of hemoglobin; its levels don’t specifically reflect hemolysis. Methemalbumin can form during hemolysis but is not the standard marker used to indicate intravascular destruction. Hemopexin binds free heme and can also be depleted in significant hemolysis, but the classic, most direct clue clinicians look for is the fall in haptoglobin due to its consumption by binding free hemoglobin.