Transferrin (TX) is a metal-combining protein that reversibly binds to acid-soluble iron in plasma. It functions to transport iron to the bone marrow and to tissue storage organs such as the liver. Transferrin also participate in the regulation and control of iron absorption and protects against iron intoxication. Like haptoglobin, the carrier of hemoglobin, transferrin is synthesized in the liver, but unlike haptoglobin transferrin is returned to the circulation after unloading its iron in the reticuloendothelial system. This ELISA kit can be used to measure transferrin in serum, tissue extracts and other biological fluids.