Serum Iron Test

The serum iron test is used to measure the amount of iron in the blood. The test is also known as the Fe²⁺ test, ferric ion test, ferrous ion test, anaemia-serum iron test.

Iron is an important mineral that plays several key roles in the body. It is needed for haemoglobin formation, which helps red blood cells carry oxygen to the tissues throughout the body. It is also a key component of many important enzymes that help the body function properly.

Abnormal levels of iron in the body can be seen in conditions such as anaemia (a condition in which there is a lack of healthy red blood cells), haemochromatosis (excess iron in the body), and iron poisoning (excess consumption of iron).

Doctors use the serum iron test to help detect conditions associated with abnormal iron levels in individuals showing symptoms of iron imbalance. The test may also be advised if your red blood cell or haemoglobin levels are abnormal in a routine complete blood count (CBC) panel or for monitoring ongoing treatment for iron-related conditions.

You may be advised to get the serum iron test if you are experiencing the following iron deficiency symptoms:

• Fatigue or weakness, especially during physical exercise
• Headaches
• Dizziness or lightheadedness
• Heart palpitations (pounding)
• Difficulty concentrating or thinking clearly
• Pale skin
• Shortness of breath
• Brittle nails
• A sore or swollen tongue
• Mouth ulcers
• Bluish tint to the whites of the eyes

You may also be advised to get the test if you are experiencing the following iron overload symptoms:

• Pain in the joints
• Fatigue
• Weakness
• Loss of weight
• Stomach pain

The test is also recommended to be done for the following categories of people:

• Pregnant women: Pregnant women are susceptible to iron deficiency because the growth of the foetus requires an additional amount of nutrients.
• Individuals already diagnosed with anaemia: Individuals already diagnosed with anaemia, especially when it is chronic (long-term), are advised to get the test as they have a deficiency of healthy red blood cells.
• Individuals with chronic disorders: Individuals with certain autoimmune disorders, such as Crohn disease (a condition associated with the digestive tract) and systemic lupus erythematosus (a condition affecting the skin, joints, brain, and other organs) are prone to anaemia of chronic disease.
• Individuals with heavy blood loss: This includes women with heavy menstrual bleeding and individuals who are frequent blood donors, as they may have a deficiency of healthy red blood cells.
• Individuals following a vegetarian or vegan diet: Plant-based diets increase the risk of low iron stores in the body.

The serum iron test is not generally needed as a part of routine check-up. However, if your red cell or haemoglobin counts are abnormal in a CBC test, you may need to take this as a follow-up test to determine the underlying cause. Other than that, the test may be required more frequently in certain situations.

Note: The information provided is meant for educational purposes only and should not be considered as medical advice. Frequency of the test may vary based on individual condition. Thus, always seek the advice of a qualified doctor to understand your need for testing, interpretation of test results, and personalised medical recommendations.

The serum iron test can be used with other tests to help detect a few conditions, such as:

• Iron deficiency anaemia: This is a condition characterised by the lack of healthy red blood cells.
• Anaemia of chronic disease: This is a condition characterised by the lack of healthy red blood cells in individuals with long term conditions that involve inflammation.
• Haemochromatosis: This is a condition characterised by excess iron in the body.
• Haemolytic anaemia: In this type of anaemia, red blood cells in the body get destroyed earlier than usual.
• Iron poisoning: This is a condition which occurs when an individual consumes more than the recommended amount of iron.
• Restless legs syndrome: This condition is characterised by a tingling or burning feeling in your legs.
• Liver diseases: This may include diseases of the liver such as alcoholic hepatitis, viral hepatitis or fatty liver disease, which can cause excessive iron absorption.

What to Expect Before the Serum Iron Test

You must fast for 10 to 12 hours before the test. During the fasting period, drink plain water freely. Avoid all food, milk, tea, coffee, juices, and beverages other than water. Avoid smoking and alcohol for at least 24 hours, as both can falsely elevate triglyceride levels. Avoid strenuous exercise in the 24 hours before the test. Continue your regular medications unless your doctor advises otherwise. Morning appointments are strongly recommended.

What to Expect During the Blood Collection

A phlebotomist cleans the skin with an antiseptic, then places an elastic band around your upper arm to make the veins easier to access. A small needle is inserted into the vein; you may feel a brief pinch. Blood is collected into a labelled tube in under a minute.

What to Expect After the Serum Iron Test

A small cotton swab and bandage are placed over the site to stop any minor bleeding. You can eat and drink immediately after the test - have a light meal as soon as possible after the fast. If dizzy, sit and relax for a few minutes.

In the serum iron test, the primary parameter being measured is:

• The amount of iron in a sample of blood.

Iron is an important mineral that is required for growth and development in the body. It is used to make haemoglobin (a protein in red blood cells). It is important for bone marrow, functioning of organs, and healthy muscles. Transferrin is a protein that transports iron throughout the body. This test measures the amount of iron bound to transferrin that is circulating in your bloodstream.

The serum iron normal range is indicated in the table below.

Note: The normal range may vary slightly depending on the analytical method, the laboratory performing the test, and individual medical conditions.

The table below provides a general interpretation of the serum iron test results based on whether the levels are low or high.

Like any other medical test, this test also has certain risks and limitations.

Risks:

The serum iron test is generally safe and involves minimal risk. You may experience slight pain when the needle is inserted or mild bruising afterwards, which usually resolves spontaneously.

Limitations:

• You may have to fast for a few hours before the test. Talk to your doctor for more specific instructions on this.
• Certain medicines such as antibiotics, birth control pills, cholesterol medicines, testosterone supplements, and deferoxamine may have an impact on test results. Consult your doctor if you need to temporarily stop taking these.
• If your test results are not normal, it does not always mean that you have a medical condition. Further testing and evaluation of clinical symptoms and history may be required.
• There are some foods that can inhibit iron uptake and have an impact on test results. These include soya beans, milk, eggs, and calcium rich foods.
• The serum iron test only measures the amount of circulating iron (bound to transferrin) in the blood. Other tests, such as a ferritin blood test (measures how much iron is stored in your body) may be required to understand the amount of actual iron reserves in the body.
• The test cannot detect the underlying cause of anaemia or which type of anaemia an individual may be suffering from. Further testing may be required to get this information.

Depending on your symptoms and results, your doctor might recommend certain additional tests to better understand your condition:

• Serum ferritin test
• Total iron binding capacity (TIBC)
• Transferrin saturation
• Complete blood count (CBC)
• Bone marrow aspiration/biopsy
• Colonoscopy
• Upper endoscopy
• Reticulocyte count
• C-reactive protein level
• Erythrocyte sedimentation rate