Methemalbumin

Methemalbumin is a complex formed by the binding of hemoglobin to albumin, more specifically methemoglobin (metHb). It is usually formed in the presence of large amounts of free hemoglobin in the blood plasma, which can occur in certain pathological conditions such as intravascular hemolysis.

Formation

Methemalbumin is formed when hemoglobin, released from the red blood cells, binds to haptoglobin. This complex is then removed by the macrophages of the reticuloendothelial system. When the binding capacity of haptoglobin is exceeded, free hemoglobin is oxidized to methemoglobin, which in turn binds to albumin, forming methemalbumin.

Clinical significance

The presence of methemalbumin in the blood is a sign of increased hemolysis. It can be detected by the Schumm's test, which is a color reaction with ammonium sulfide. Methemalbumin is also involved in the formation of Heinz bodies, which are seen in conditions like G6PD deficiency and thalassemia.

See also

• Hemoglobin
• Methemoglobin
• Haptoglobin
• Heinz bodies