Diagnostic Use
1. Iron Deficiency:
The soluble transferrin receptor (sTfR) concentration is increased in iron deficiency. The developing red cells regulate their iron uptake by increasing the number of transferrin receptors on their surface, and the number of sTfR in serum increases in parallel.
2. Anaemia of chronic disease (ACD)
sTfR measurement may be useful for differentiating anaemia caused by iron deficiency from ACD.
ACD can be found in inflammatory conditions including infection, autoimmune disorders and cancer. The pathogenesis of ACD is complex. ACD may be associated with normal sTfR levels. However, a functional Fe deficiency may develop due to failure to release iron from stores, accompanied by increased STfR levels.
It has been suggested that a trial of iron supplementation therapy could be considered in ACD patients if the sTfR level is raised (ref 1).
3. Other Conditions:
An increase in sTfR may be found in conditions where there is ineffective erythropoiesis, such as myelodysplastic syndromes, or in any condition where there is an increase in erythropoietic activity. This is due to an increase in erythropoietic progenitor cells, which have a high concentration of cell surface transferrin receptors.
The increase is usually minimal when associated with thalassaemia, autoimmune haemolytic anaemia, hereditary spherocytosis, sickle cell anaemia (with associated hypersplenism), megaloblastic anaemia, or secondary polycythaemia, but may be up to twice normal concentration in myeloproliferative disorders. These conditions are identifiable by using other haematological tests.
Conversely, sTfR concentration may decrease in aplastic anaemia, or any other condition where erythropoietic activity is reduced.
References
Chang J, Bird R, Clague A, Carter A. Clinical utility of serum soluble transferrin receptor levels and comparison with bone marrow iron stores as an index for iron-deficient erythropoiesis in a heterogeneous group of patients. Pathology. 2007;39:349-353
Uncertainty of Measurement
Uncertainty of Measurement: 0.3mg/L at level of < 2.0 mg/L
4% at level of 5 mg/L and higher