Ferritin Test: Normal Range, Low & High Causes

Understanding Ferritin: Your Body's Iron Warehouse

When a patient sits in my clinic describing crushing fatigue, brittle nails, and a nagging shortness of breath during their morning walk, ferritin is often the first thing I check. Ferritin is a protein that stores iron inside your cells, releasing it when the body needs it. Think of it as your personal iron warehouse — if the warehouse is empty, your cells can't make enough healthy red blood cells, and you feel the effects throughout your body.

This test measures the amount of ferritin circulating in your blood. Unlike serum iron which fluctuates with meals, ferritin gives a stable snapshot of your body's iron reserves. In my experience, patients are often surprised how much this single number can reveal about energy levels, immune function, and even mood.

When Should You Get a Ferritin Test?

I typically recommend checking ferritin levels when someone reports persistent fatigue, pale skin, frequent headaches, or an unusual craving for ice or dirt (a condition called pica). Other indicators include restless legs, hair thinning, and a feeling of being cold all the time — particularly in women who have heavy menstrual periods.

On the flip side, high ferritin can also cause symptoms. Joint pain, abdominal discomfort, unexplained weight loss, or a bronze tint to the skin can signal iron overload. I've seen many patients who dismissed these signs as 'getting older' until their ferritin came back sky-high.

Ferritin Normal Ranges by Age and Gender

Reference ranges vary between laboratories, but the table below shows typical values used in NHS and Mayo Clinic protocols. Always interpret your result with your doctor's guidance.

Note: Units may vary (µg/L is equivalent to ng/mL). Some labs use reference intervals based on local population.

What Does Low Ferritin Mean?

Low ferritin is the earliest sign of iron deficiency — often appearing before your hemoglobin drops and you become anaemic. In my clinic, I see this most frequently in women due to menstrual blood loss, in vegetarians and vegans who absorb less heme iron, and in people with gastrointestinal conditions like coeliac disease or Crohn's.

Symptoms of low ferritin include severe fatigue, brain fog, shortness of breath with exertion, brittle nails, and hair loss. Some patients describe feeling 'washed out' even after a full night's sleep. If left untreated, iron deficiency progresses to iron deficiency anaemia, which can strain the heart.

How to Increase Ferritin Levels

Dietary changes come first. Iron-rich foods include red meat, liver, spinach, lentils, and fortified cereals. Pair them with vitamin C (like a glass of orange juice) to boost absorption. In many cases, an oral iron supplement is needed — I typically prescribe ferrous sulphate or ferrous fumarate. But don't oversupplement; too much iron can be toxic. Always test before treating.

Can High Ferritin Be Dangerous?

Yes, elevated ferritin should not be ignored. High levels can indicate iron overload (haemochromatosis), a genetic condition where your body absorbs too much iron. Over years, excess iron deposits in the liver, heart, pancreas, and joints, causing cirrhosis, cardiomyopathy, diabetes, and arthritis. I've diagnosed haemochromatosis in patients who came in for 'routine check-ups' with ferritin over 1000 ng/mL.

Other causes of high ferritin include chronic inflammation (e.g., rheumatoid arthritis, infections, cancer), liver disease (fatty liver, hepatitis), and alcohol misuse. In these cases, ferritin rises as an acute phase reactant — it's a red flag that needs further investigation.

Ferritin During Pregnancy

Pregnancy dramatically increases iron needs — your body must produce extra blood for the growing baby, and the placenta itself requires iron. Ferritin levels often fall in the second and third trimesters. In my obstetrics practice, we screen all pregnant women and treat low ferritin to prevent preterm birth, low birth weight, and maternal fatigue.

Normal ferritin in pregnancy is debated, but most experts aim for levels above 30 ng/mL. I counsel my patients to start a prenatal vitamin with iron early on, and to eat iron-rich foods like lean meat and dark leafy greens.

How to Prepare for a Ferritin Blood Test

No special preparation is needed for a ferritin test. You can eat and drink normally before the blood draw. However, certain factors can affect results — acute infections, recent blood transfusions, or high-dose vitamin C supplements may skew levels. Let your doctor know if you've been ill recently or if you take supplements.

The test is a simple venipuncture, done at your doctor's office or a lab. Results typically come back within 24–48 hours. I always interpret ferritin alongside other markers like haemoglobin, transferrin saturation, and total iron-binding capacity (TIBC) to get the full picture.

Ferritin vs. Other Iron Tests: What's the Difference?

Many patients ask me: 'Why not just check my iron level?' Serum iron changes throughout the day and after meals, making it unreliable alone. Ferritin is more stable and reflects storage iron. Transferrin saturation tells you how much iron is actually being transported. Together, these tests paint a complete portrait of your iron status — like checking both your bank account balance and your monthly spending.

When to See a Doctor

If you have persistent fatigue, unusual cravings, or joint discomfort that doesn't go away, ask for a ferritin test. It's a simple, inexpensive blood test that can uncover treatable conditions. Don't wait until you feel 'really sick' — early detection of iron disorders can prevent long-term complications. In my practice, I've seen ferritin testing transform lives, from restoring energy to reversing early organ damage.