Diagnostic Use
Plasma iron concentrations are generally higher in the morning, but the diurnal variation is inconsistent. Concentrations may also vary widely from day to day in the same patient.
Causes of increased plasma iron : iron poisoning, haemochromatosis, anaemias which are not due to iron deficiency especially when treated with transfusions, and liver disease.
Causes of decreased plasma iron : iron deficiency anaemia, anaemia associated with chronic disorders.
TIBC (transferrin): increased in iron deficiency. Decreased in iron overload, inflammation & infection, and liver disease.
Differentiating iron-deficiency anaemia from that of chronic disease can be difficult. Ferritin is helpful if it is low. However ferritin is increased nonspecifically in many inflammatory disorders; the ferritin concentration may be normal, or increased, even though the patient is iron deficient. Measurement of the level of soluble transferrin receptors (sTfR ) may be helpful in this context.
Test Method
Principle: Colorimetric Assay
Analysers: Roche Diagnostics Cobas c703
Reagents: IRON2
Limitations / Interference
Note: Recent intravenous iron infusion (such as ferric carboxymaltose) significantly increases serum iron. The half-life of ferric carboxymaltose is about 12hrs, however given the large iron load with a single dose it would not be recommended to repeat iron studies for at least 10 days without clear indication.