Transferrin receptor screening
Soluble transferrin receptors are proteins found in blood that can be elevated with iron deficiency. This test measures the amount of soluble transferrin receptors to help detect and evaluate iron deficiency and aid in the diagnosis of iron deficiency anemia.
Iron is an essential nutrient absorbed from the diet. Transferrin is the main protein in the blood that binds to iron and carries it to tissues and cells throughout the body. About 80% of iron is transported to the bone marrow, where it is incorporated into the hemoglobin in red blood cells (RBCs), and the rest is stored in other cells and tissues as ferritin and hemosiderin.
When transferrin binds to iron, they form a complex. These complexes bind to transferrin receptors found on the surface of cells and the iron is then transported into the cells. Transferrin receptors are cleaved from the surface of cells, enter the bloodstream, and become soluble transferrin receptors (sTfR).
The number of transferrin receptors found on the surface of cells correlates with the level of iron within cells. When the iron level drops, the cells produce more transferrin receptors. As more receptors are produced, more are cleaved from cell surfaces and enter the blood, increasing the level of soluble transferrin receptors. Thus, measuring the level of sTfR is one way of evaluating the amount of iron available in the body.
Red blood cells have a lifespan of about 120 days. Because of this, the bone marrow must continually produce new RBCs. If there is insufficient iron taken in through the diet and/or increased iron loss (e.g., bleeding), iron reserve stored in the body is decreased. Over time, this can lead to iron deficiency, as the amount of iron stored in the body exhausts and the demand for iron exceeds the supply. As a result, fewer RBCs are produced and those newly formed RBCs are also smaller (microcytic) and contain less hemoglobin (hypochromic). This is a condition called iron deficiency anemia.
- Sample of blood serum
- We perform the test in 48 hours from sampling