Tests and referrals · Iron studies
What do ferritin and iron blood tests tell me?
Ferritin, haemoglobin and the other parts of iron studies answer different questions. Understanding the pattern can help you discuss the cause, treatment and follow-up with a GP.
What do ferritin and iron blood tests tell me?
Ferritin gives an estimate of your stored iron, while the other parts of iron studies help show how iron is being carried and made available in your blood. The results need to be read together with your full blood count, symptoms and health context. A GP can explain the pattern, look for a cause and plan any treatment or follow-up.
Ferritin and haemoglobin answer different questions
Ferritin is a protein that stores iron. A low ferritin result usually points to low iron stores, which can develop before anaemia appears.
Haemoglobin is the oxygen-carrying protein inside red blood cells. It is measured in a full blood count (FBC), sometimes called a full blood examination. Anaemia means that haemoglobin or healthy red blood cells are below the expected range. You can therefore have iron deficiency without anaemia, and anaemia can have causes other than iron deficiency.
The FBC also reports features of the red blood cells that give the GP more context. No single result should be used to work out the cause on its own.
What else is included in iron studies?
An iron-studies report may include several results that need to be interpreted together:
- Serum iron is the iron circulating in your blood when the sample was taken. It can change with recent intake and time of day, so it is not a reliable measure of total iron stores by itself.
- Transferrin is the main protein that carries iron through the blood. A laboratory may instead report total iron-binding capacity, which is related to transferrin.
- Transferrin saturation is a calculation showing how much of transferrin's iron-carrying capacity is being used.
- Ferritin gives an estimate of stored iron.
The pattern can help distinguish depleted stores from reduced iron availability during inflammation and can help investigate possible iron overload. It still needs to be read alongside your history and other tests.
What can a low, normal or high ferritin result mean?
Low ferritin
A low ferritin result usually means iron stores are low. The GP will also consider whether haemoglobin is low and whether symptoms, the FBC and other iron results fit iron deficiency. Low iron and iron-deficiency anaemia are related, but they are not the same diagnosis.
Ferritin in the reference range
A result inside the laboratory's reference range does not answer every iron question. Ferritin can rise during inflammation or infection, so a normal or high result can sometimes mask iron deficiency. Inflammation can also reduce how much stored iron is available for the body to use. The GP may look at transferrin saturation, inflammatory markers, the FBC and the wider clinical picture when the results do not fit together.
High ferritin
High ferritin does not automatically mean there is too much iron in the body. Inflammation, infection, liver conditions, alcohol use and metabolic health can raise it. Iron overload is another possibility, and transferrin saturation and further assessment help the GP decide what needs investigating. Do not try to lower ferritin by donating blood or changing treatment without medical advice.
Reference ranges vary between laboratories and depend on the test method and clinical context. A number close to a boundary is not a diagnosis or a treatment target by itself.
Why might iron stores become low?
Finding low iron is only part of the work. The next question is why it happened. The likely cause depends on age, periods, pregnancy, symptoms, diet, medicines, health conditions and previous results.
- Ongoing blood loss, including heavy periods or bleeding from the digestive system.
- Pregnancy or another time when the body needs more iron.
- Not getting enough usable iron from food.
- Difficulty absorbing iron, including from coeliac disease or inflammatory bowel disease.
- Blood donation or another source of repeated blood loss.
A GP may recommend more questions, examination, repeat blood tests or other investigations rather than assuming diet is the explanation.
Do I need to fast before iron studies?
Do not assume that every ferritin or iron test requires fasting. Preparation depends on the tests requested, the laboratory and whether other blood tests are being collected at the same time. Some iron-studies requests need a morning fasting sample or instructions about iron supplements; others do not.
Follow the instructions on your referral or from the collection centre. Check before the test if the instructions are unclear. Do not stop prescribed medicines or supplements unless the requesting clinician tells you to.
What happens if I am pregnant?
Pregnancy increases iron needs, and anaemia is checked with blood tests during antenatal care. Ferritin and other tests may be used when the maternity team needs more information about iron stores or the cause of anaemia.
Discuss the result and any treatment with the GP, midwife or obstetric team caring for the pregnancy. Do not start, stop or increase iron because of one result without checking the plan.
How are low iron results treated and followed up?
Treatment depends on the result, symptoms, likely cause, pregnancy status, other health conditions and what you have already tried. It may include changes to food, oral iron, or treatment given another way when a clinician decides that is needed. The plan should address the cause as well as replacing iron.
A repeat blood test may be needed to check whether haemoglobin and iron stores are recovering. If treatment is not working or causes side effects, ask for review rather than changing the dose yourself. HerDoc does not provide iron infusions; if an infusion or other in-person treatment is recommended, the GP can explain the next step and you will need to arrange it with an appropriate local service.
How can a HerDoc GP help?
A HerDoc GP can discuss symptoms and previous results, order an FBC or iron studies when indicated, and help interpret a report. You can ask about a particular test or explain what has changed and ask what the GP recommends.
If a HerDoc GP orders the test, the pathology provider collects the sample. Results generally return to HerDoc, and you can book a separate appointment to discuss them. Ask what follow-up is needed and when. Tests or examination in person may be needed to investigate a cause that cannot be assessed by phone.
Have the full report, its date, medicines and supplements, pregnancy context, period or bleeding changes, diet, digestive symptoms and earlier treatment handy. Do not assume that no news means the result needs no follow-up.
When should I seek help sooner?
Seek prompt medical care for black or bloody bowel motions, vomiting blood, bleeding that is suddenly much heavier than usual, marked weakness, worsening breathlessness, fainting or a racing heartbeat with feeling unwell.
Call 000 for collapse, severe breathing difficulty, chest pain or another emergency. If you are pregnant and feel very unwell, faint, short of breath at rest or have heavy bleeding, contact your maternity service or seek urgent local care. Do not wait for a routine online result discussion.
Sources and further reading
Australian sources supporting this guide. Source organisations have not reviewed or endorsed HerDoc.
When telehealth may not be suitable
- Active severe bleeding
- Collapse or severe breathing difficulty
- Symptoms needing immediate examination or treatment
When to seek urgent care
Call 000 for collapse, severe breathing difficulty, chest pain or another emergency. If you are pregnant and feel very unwell, faint, short of breath at rest or have heavy bleeding, contact your maternity service or seek urgent local care.
- Black or bloody bowel motions or vomiting blood
- Heavy bleeding with weakness or fainting
- Breathlessness at rest or chest pain
- A racing heartbeat with feeling unwell