Serum Iron

Iron status, anaemia

This test measures the amount of iron circulating in your blood, mostly carried by a protein called transferrin. Iron is needed to make haemoglobin, which carries oxygen in red blood cells. Serum iron changes a lot through the day and after meals or supplements, so it is usually read with TIBC, transferrin saturation and ferritin rather than on its own.

• To help find the cause of anaemia
• Tiredness, weakness or pale skin that might relate to low iron
• To look for iron overload, when the body stores too much iron
• To check the response to iron treatment
• As part of an iron profile with TIBC and ferritin

Eat and drink as you usually would. Recent iron tablets or iron-containing supplements raise the level, so tell your doctor if you take them; your doctor may suggest having the sample before your next tablet. A morning sample is often preferred because iron is usually higher earlier in the day.

Sample

Blood sample

How it works

Book a morning slot if you can. The trained collector takes a small blood sample from a vein in your arm, which takes a few minutes, and labels it before it goes to the laboratory.

Report

Within 24 hours of collection.

The report shows your serum iron against the laboratory's range. A low level can point to iron deficiency, a common cause of anaemia, but it can also fall during infection or inflammation. A high level can follow recent iron intake or, less often, iron overload or some anaemias. Because a single iron value varies so much, your doctor will read it with ferritin and TIBC before reaching a conclusion.

One test: Serum Iron, from one blood sample.