What Is the Iron, Serum Test?

The Iron, Serum test measures the level of iron circulating in your bloodstream. Iron is an essential mineral that plays a central role in the production of red blood cells, primarily through its presence in haemoglobin, the protein responsible for carrying oxygen throughout your body.

Doctors may order this test when symptoms like fatigue, dizziness, pale skin, or shortness of breath are present. It helps identify iron deficiency, iron overload, and other underlying conditions. The procedure involves a simple blood draw followed by lab analysis to determine how much iron is present in your blood.

Iron is critical to many bodily functions, but its most important job is helping red blood cells transport oxygen. It does this by forming haemoglobin, which binds oxygen in the lungs and releases it to tissues across the body. Iron also supports energy production, immune function, and brain development.

When your iron levels fall too low, it can lead to anaemia. On the other hand, excess iron in the blood can be toxic and damage vital organs over time. Monitoring iron through a serum test helps assess whether your levels are within the healthy range.

Doctors may recommend a serum iron test to:

• Diagnose or confirm iron deficiency anaemia
• Monitor iron levels in people taking iron supplements
• Investigate symptoms of fatigue, weakness, or pale skin
• Assess conditions related to iron overload like haemochromatosis
• Track recovery after treatment for anaemia

This test may also be used alongside other blood tests, such as Total Iron Binding Capacity (TIBC), ferritin, or transferrin saturation, to offer a complete picture of your iron status.

Your doctor might suggest an Iron, Serum test if you:

• Show symptoms like persistent tiredness, dizziness, or shortness of breath
• Have a known history of anaemia or chronic blood loss
• Are being treated for iron deficiency or excess iron
• Have a family history of haemochromatosis or similar conditions
• Are pregnant or have increased iron needs

It’s also useful for individuals undergoing evaluation for malabsorption conditions, such as celiac disease or inflammatory bowel disease.

The Iron, Serum test is often performed along with related markers to give a more accurate picture of iron metabolism:

• Serum Iron: The amount of iron present in the blood.
• Total Iron Binding Capacity (TIBC): Indicates the blood’s capacity to bind iron with transferrin.
• Unsaturated Iron Binding Capacity (UIBC): The portion of transferrin not yet bound to iron.
• Transferrin Saturation: The percentage of transferrin that is bound with iron.
• Ferritin: Reflects stored iron in the body, helping differentiate between iron deficiency and inflammation-related anaemia.

Together, these help determine whether you have too little or too much iron in circulation and storage.

A healthcare provider will draw a small blood sample from a vein in your arm, usually after cleaning the site with antiseptic. The sample is then sent to a laboratory where chemical reagents are used to extract and measure the iron concentration. Spectrophotometric analysis helps calculate the exact levels.

You may be asked to fast for 8 to 12 hours before the test, as food intake can temporarily affect iron levels in your blood. Only water is typically allowed during this period.

Let your doctor know about any supplements or medications you’re taking, including iron pills, multivitamins, birth control, or corticosteroids, as these can influence the results.

During the test, you might feel a brief prick as the needle enters your vein. Once the blood is drawn, the site will be covered with a bandage. Most people experience little to no discomfort afterward, though some minor bruising can occur.

The results usually take 1 to 2 days and will be reviewed in the context of your symptoms and medical history.

Normal ranges can differ slightly depending on the lab, but in general:

Men: 60 to 170 mcg/dL

Women: 50 to 140 mcg/dL

These values help assess whether your body has an adequate supply of iron or if further evaluation is needed.

Low serum iron may suggest:

• Iron deficiency anaemia
• Chronic blood loss (e.g., gastrointestinal bleeding)
• Poor dietary intake or malabsorption
• Chronic illnesses affecting iron utilisation

High serum iron may point to:

• Iron overload disorders like haemochromatosis
• Repeated blood transfusions
• Liver conditions

Certain types of anaemia (e.g., haemolytic anaemia)

If your test results are abnormal, your doctor may recommend further tests or treatments depending on the underlying cause.

To keep your iron levels in balance:

• Eat iron-rich foods such as lean meats, beans, lentils, spinach, and fortified cereals.
• Pair iron sources with vitamin C-rich foods to improve absorption.
• Avoid excessive iron supplements unless prescribed by a doctor.
• Monitor blood levels if you have a chronic condition or are pregnant.
• Stay hydrated and eat balanced meals around the time of your test for consistent readings.

After the test, you can return to normal activities. Apply light pressure to the puncture site to prevent bruising. Watch for signs of infection like redness or swelling, though these are rare.

Discuss your results in detail with your doctor. If your levels are outside the normal range, follow up promptly to understand the next steps whether that means adjusting your diet, changing medication, or undergoing further tests.