Iron in the blood: normal levels in women and men, high and low values

An "iron test" is not a single measure but a group of tests: serum iron, transferrin, total iron-binding capacity, ferritin. We explain what the numbers on the form mean, where normal ends, and what deviations indicate.

Why iron in the blood is measured

Iron is needed for the synthesis of hemoglobin — the protein in red blood cells that carries oxygen from the lungs to tissues; it is also involved in muscle function, bone marrow activity, and the production of certain hormones. Iron tests are ordered to detect too low a level (a sign of anemia, although low iron can occur without anemia), too high a level (suspected hemochromatosis, i.e., iron overload), to assess iron stores in the liver in liver disease, to check for restless legs syndrome and adult-onset Still's disease, and to monitor the effect of treatment.

Blood iron levels vary throughout the day and may be higher in the morning. The test is often taken in the morning and on an empty stomach, after up to 12 hours without food; specific preparation is prescribed by the doctor.

Normal serum iron in women and men

There is no single normal number for everyone: the result is interpreted taking into account symptoms, age, medical history, and other tests.

In women, the level may be lower during menstruation. Contraceptives and estrogen-containing drugs affect iron levels.

Transferrin and iron-binding capacity

Transferrin is a protein that transports iron throughout the body. Total iron-binding capacity shows how well iron binds to transferrin and other blood proteins.

High iron in the blood: possible causes

Elevated values suggest hemochromatosis (hereditary or associated with another disease), lead poisoning, and liver diseases. Signs of excess are nonspecific: weakness and fatigue, joint pain — more often in the knees or hands, abdominal pain, decreased interest in sex or erectile dysfunction, skin discoloration to gray, metallic, or bronze.

Low iron: what a decreased level means

A low level occurs in iron deficiency anemia — the most common type of anemia, in other types of anemia, and in thalassemia, an inherited disorder of red blood cell formation. Deficiency does not cause symptoms for a long time; when they appear, they include fatigue and lack of energy, shortness of breath, noticeable palpitations, pale skin, and headaches. Less common are tinnitus, painful tongue, hair loss, and restless legs syndrome.

• Common causes are heavy menstruation and pregnancy.
• Bleeding from the stomach and intestines: NSAIDs (ibuprofen, aspirin), ulcers, inflammation of the intestines or esophagus, hemorrhoids; tumors of the stomach and intestines are less common.
• Increased demand: frequent blood donors, pregnancy and breastfeeding, premature infants and low birth weight babies.
• Underlying conditions: cancer, digestive diseases, heart failure.
• Risks without treatment: higher risk of infections, heart and lung complications (tachycardia, heart failure), greater risk of pregnancy and childbirth complications.

Daily iron requirement and when to see a doctor

There is no single "daily iron norm" for everyone: the requirement depends on age, sex, and how plant-based the diet is.

Diagnosis begins with a complete blood count — it shows the number of red blood cells and other cells. Then the doctor may order ferritin, transferrin, iron-binding capacity, and if the cause is unclear — a fecal occult blood test and a referral to a specialist. In case of deficiency, the cause is sought: for example, an ulcer or heavy periods.

An abnormal iron level alone is not a reason to call an ambulance; 103/112 — if the condition is life-threatening (for example, signs of a heart attack or stroke).

See a doctor if you have symptoms of iron deficiency or excess, if values on the form are abnormal, or if you have unexplained fatigue and shortness of breath. This material is for reference: the numbers are interpreted by a doctor, and this is not a treatment recommendation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer