What kind of doctor treats iron deficiency? Who to see, which blood tests come first and what you will be asked

You have felt tired for a while, and more hair comes out when you brush it. Who checks your iron? Usually your GP or primary care doctor, and the answer comes from a blood test, not a hunch. Until then, log symptoms in Sam's symptom diary instead of on paper; the monthly report you create shows the symptom days of a finished month as a calendar.

This guide covers the path to a result. It explains who to see, which tests come first and what you will be asked. What the numbers on your report mean is in Iron deficiency: ferritin and hemoglobin explained. What Sam keeps for iron deficiency is in the iron deficiency overview.

What kind of doctor treats iron deficiency?

Start with your GP or primary care doctor. The NHS advises seeing a GP if you think you might have iron deficiency anemia. Your doctor asks about your lifestyle and medical history, may examine you and orders the blood test.

Who comes in later depends on what the tests show:

Healthdirect Australia names the gastroenterologist and the gynecologist. For new iron deficiency anemia with no obvious cause, the British Society of Gastroenterology (BSG, 2021) also advises considering an urgent look at the gut. The urologist step comes from the Onkopedia guideline. The hematologist step rests on the US National Heart, Lung, and Blood Institute (NHLBI) alone, which names it for anemia in general. With heavy periods, your GP may run blood tests for conditions such as iron deficiency anemia, the NHS says. They may also refer you for tests or to a specialist. Which doctor you need, and when, is for your care team to decide.

How do doctors test for iron deficiency?

With questions, an examination and a blood test. Your doctor will ask about your health and what you eat and may examine you, says healthdirect. The only reliable way to tell is a blood test.

The NHS starts with a full blood count (FBC). The German hematology guideline (Onkopedia, by the society DGHO) explains which iron test comes first. It recommends serum ferritin as the first-line test. Unlike the other lab tests, ferritin already shows low iron stores. Per the guideline, three values together confirm iron deficiency as the cause of anemia in most cases.

• Ferritin: reflects your iron stores.
• MCV from the blood count: the size of your red blood cells. In iron deficiency anemia they are typically too small.
• CRP: an inflammation marker. It matters because inflammation can push ferritin up and hide a deficiency.

For people with blood disorders or cancer, the guideline adds a second iron test, such as transferrin saturation. It calls serum iron on its own obsolete for this purpose; the ferritin and hemoglobin guide explains why.

This guide leaves out cut-offs on purpose. They are tools for your doctor, not a test you can read yourself. A normal-looking value is not an all-clear. The cut-offs that WHO and the guideline use are in the ferritin and hemoglobin guide.

Do you need to fast? The NHS says you do not need to prepare for a full blood count. MedlinePlus says your provider may ask you to fast for 12 hours before a ferritin test. It is usually done in the morning. Ask when you book.

Which symptoms are worth getting checked?

The ferritin and hemoglobin guide lists the symptoms in detail. These are the usual reasons to get tested.

• Tiredness, exhaustion, poor concentration, dizziness or restless legs you cannot explain. The Onkopedia guideline describes some of them even in iron deficiency without anemia. Healthdirect notes that you may just feel tired and run down.
• A blood count with low hemoglobin or hematocrit. MedlinePlus names this as a reason for a ferritin test.
• Heavy periods. The NHS says blood tests can then check for iron deficiency anemia.
• Blood donation. The guideline names blood donors as a group at particular risk.

What about hair loss? The NHS lists it among the less common symptoms of iron deficiency anemia. Its hair loss page names iron deficiency as one possible temporary cause, along with illness, stress and weight loss. A GP may be able to tell the cause just by looking at your hair. Whether iron gets tested is their call.

All of these can have other causes. A racing heart and shortness of breath can be urgent. When not to wait for an appointment is in the next section.

When should you skip the waiting list?

• Call your local emergency number (112 in the EU, 999 in the UK, 911 in the US) for chest pain or severe shortness of breath (barely able to speak). Call too for vomiting blood, black sticky stool, blood in the stool beyond traces on the toilet paper, or heavy bleeding that cannot be stopped. A racing, pounding or irregular heartbeat is an emergency too if it does not go away or comes with shortness of breath, chest pain or feeling faint. For fainting, call when it comes with chest pain or a racing or irregular heartbeat. Call too if it happens during exercise or while lying down, or comes with shaking or jerking, a serious injury or difficulty speaking or moving. Also call if the person is not breathing, cannot be woken within a minute or does not fully recover. Do not wait for it to pass, and do not drive yourself to the emergency department. Dark stool can also come from iron supplements; black, sticky stool still calls for emergency help, and if you are unsure, get it checked soon.
• Get checked by a doctor the same day for shortness of breath that is worse than usual or a new racing or irregular heartbeat that has stopped. The same goes for a very heavy period with dizziness or weakness, or bleeding that is suddenly much heavier than usual. When your practice is closed, use the urgent care service where you live (111 in the UK).
• Get checked soon for fainting without those signs once you have fully recovered, for very heavy periods and for any trace of blood in the stool.

What will the doctor ask before the blood test?

The cause of iron deficiency always has to be found, the Onkopedia guideline says. So the work-up starts with targeted questions. The guideline lists these topics:

• Periods: how long and how heavy they are.
• Bleeding, bowel habits and hemorrhoids.
• Diet: the guideline names a strict vegetarian diet among the reasons for low iron intake.
• Medicines: on some medicines, even healthy people can develop iron deficiency from chronic gut bleeding, the guideline says. Do not stop a prescribed medicine on your own; talk to your doctor first.
• Blood donation, infections and operations.

The NHLBI adds questions about your medical history, what you eat and whether relatives have anemia.

For medicines, bring a list of everything you take, including over-the-counter products and supplements. The medication list guide covers what belongs on it. If you already take iron, put it on the list. Healthdirect advises seeing your doctor before taking any iron supplements.

In Sam you can prepare the answers. The symptom diary takes one entry per symptom and day: mild, moderate or severe, or simply present. There is no time of day. The cycle tracker keeps bleeding days, flow and how bleeding affected your day. You pick from set choices such as "Needed two products at once". What you take, including over-the-counter products, goes into the medication list. Its catalog is a selection, not a recommendation; check the strength on your pack.

You create the monthly report for the previous month yourself. It shows your symptom days as a calendar and your top five symptoms. It needs notifications, access to your health data and an entry on chronic conditions ("none" counts). From the second report on, it also needs your daily status (Good, A bit off or Sick) on at least 15 of the last 30 days. Symptom entries do not count. A fuller list for any visit is in the doctor appointment checklist.

When do doctors check the stomach and bowel?

The Onkopedia guideline puts one question first: is there chronic blood loss from the digestive tract? It describes these steps.

1. History and physical examination, including feeling the abdomen and a rectal examination.
2. A stool test for hidden blood. A negative result is not an all-clear and does not end the work-up: in about half of people with bowel cancer, the guideline notes, this test comes back negative.
3. If no other clear cause is present, a camera test of the stomach and bowel follows: gastroscopy and colonoscopy.
4. Tests of the small bowel if stomach and colon look normal but suspicion remains, especially with blood in the stool. Blood in the urine leads to a urology work-up.

The MSD Manual looks at men and at women whose periods have stopped. In them, iron deficiency usually points to bleeding in the digestive tract. If the cause is unclear, the NHS says, your GP may arrange a stool test. They may also refer you to a specialist. The BSG (2021) does not recommend using the immunochemical stool test (FIT) to rule out bowel cancer here; the evidence is too thin. Whether and when you need a camera test is for your doctor to discuss with you.

Waiting for a referral? If symptoms get worse or new ones appear, contact your doctor sooner. For the signs in the section "When should you skip the waiting list?", do not wait at all.

Log symptoms in Sam until your blood test

You bring dated symptom days and a full list of what you take to the visit, not guesses from memory.

• Instead of paper: fatigue, dizziness, racing heart or hair loss go into the symptom diary per day, with a strength.
• Instead of memory: the monthly report you create for the previous month shows symptom days as a calendar and your top five symptoms.
• Instead of loose packs: the medication list holds over-the-counter products too.
• Instead of guessing about periods: the cycle tracker keeps bleeding days, flow and the effect on your day.

Sam does not measure iron and cannot tell low iron from other causes of tiredness. More in the iron deficiency overview.

Try Sam for free

Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any disease or health condition. Always consult qualified professionals for medical decisions.

Related reading

• Iron deficiency: ferritin and hemoglobin explained
• Iron deficiency and heart rate: what a watch cannot measure
• Symptom diary: paper template or app?
• Doctor appointment checklist for a chronic condition
• Medication list for your doctor: what to include

Sources

Updated: October 2026

• DGHO: Onkopedia guideline Eisenmangel und Eisenmangelanämie (Hastka J, Metzgeroth G, Gattermann N; April 2025, in German), sections 2.4, 3.1, 3.3, 3.5.5, 3.5.6, 3.6.1 and 3.6.2
• NHS: Iron deficiency anaemia and Iron deficiency anaemia: treatment (last reviewed 26 January 2024), Heavy periods (last reviewed 19 September 2024) and Hair loss (last reviewed 24 January 2024)
• Healthdirect Australia: Iron deficiency (last reviewed April 2025)
• NHLBI (National Institutes of Health): Anemia: Diagnosis (updated 18 December 2025)
• MedlinePlus (US National Library of Medicine): Ferritin blood test (updated 18 March 2025)
• British Society of Gastroenterology: Guidelines for the management of iron deficiency anaemia in adults (Snook J et al., Gut 2021), statements 2 and 10 and the section on faecal immunochemical testing
• MSD Manual Consumer Version: Iron deficiency anemia (full review April 2026)
• Urgency tiers as in the ferritin and hemoglobin guide: NHS Heart palpitations (last reviewed 17 March 2026), Stomach ulcer (last reviewed 12 August 2025), Shortness of breath (last reviewed 30 January 2024) and Fainting (last reviewed 17 August 2026); Healthdirect Australia Heavy periods (last reviewed March 2026); MSD Manual Gastrointestinale Blutung (reviewed June 2025, in German); British Red Cross Learn first aid for an adult bleeding heavily