Low iron in test results is a common finding. Iron is needed for red blood cells to carry oxygen, so its shortage affects the entire body. Let's look at where deficiency comes from and what happens if it goes unnoticed.
What iron deficiency is and how it develops
Red blood cells live 3–4 months, are produced by the bone marrow, and old ones are removed by the spleen. The body gets iron from food and reuses it from old cells.
Deficiency begins when stores are depleted: we lose more than we replenish. First comes the latent stage, with hemoglobin normal. Then iron deficiency anemia develops—the most common form. Anemia is when there are not enough healthy red blood cells.
Latent iron deficiency and anemia: what's the difference
Latent, that is hidden, iron deficiency is a decrease in iron in tissue stores and serum with normal hemoglobin. Symptoms are nonspecific, and a routine blood test often shows nothing.
The difference is in the stage. With latent deficiency, hemoglobin is still normal; with anemia, there are already not enough healthy red blood cells.
How common it is: latent iron deficiency in Europe and Russia occurs in 30–40% of people, and in some regions in 50–60%. According to WHO data, iron deficiency occurs in 20–25% of infants, 46% of children aged 5–14, and 48% of pregnant women.
Causes of low iron in the blood
There are several causes, and they often add up: we lose more blood and iron than we replenish; iron is poorly absorbed; there is too little of it in food; the requirement is higher during pregnancy.
Frequent blood loss—heavy menstruation, pregnancy, bleeding in the stomach and intestines. These are caused by long-term use of ibuprofen or aspirin, stomach ulcers, inflammation of the intestines or esophagus, hemorrhoids, and less often cancer. Absorption is impaired by celiac disease, Crohn's disease, gastric bypass, excess antacids or tetracycline. Iron is low in the diet with strict vegetarianism and with a lack of iron-containing foods.
Iron shortage in the body in women: specific features
In women, the most common causes are heavy periods and pregnancy. During pregnancy, deficiency is more often associated with a lack of iron in the diet, while the requirement increases.
Heavy, prolonged, or frequent periods are one of the common causes of iron loss. During pregnancy and breastfeeding, the need for iron is higher, and the usual diet often does not provide enough.
Consequences of low iron in the blood
A shortage can be suspected based on several signs:
- fatigue, lack of energy, weakness with usual exertion, difficulty concentrating;
- shortness of breath, noticeable palpitations, headaches, pale skin, dizziness;
- hair loss, brittle nails, painful tongue, cracks at the corners of the mouth;
- less often—tinnitus, a strange taste of food, a craving to eat ice or paper, difficulty swallowing, restless legs.
Without treatment, deficiency affects various systems: there is a higher risk of infections because iron influences immunity; complications from the heart and lungs appear—tachycardia, heart failure; in pregnant women there is a greater risk of complications before and after childbirth.
How deficiency is identified and when a doctor is needed
They start with a complete blood count: it shows the number of red cells and other blood cells. Then the doctor may order iron markers—serum iron, total iron-binding capacity, ferritin, and sometimes reticulocytes.
Ferritin is the most sensitive test for early detection of deficiency: the threshold is below 30 µg/L. Laboratories often set the lower limit at 10–20 µg/L, so the result is interpreted together with complaints. If the cause is unclear, they look for the source of blood loss: a fecal occult blood test, colonoscopy, esophagogastroscopy, and examination of the urinary tract and uterus.
People go to a doctor if there are symptoms of iron deficiency, if blood is visible in the stool, or if the stool has become black and tarry.
Low iron by itself is not a reason to call an ambulance. 103 or 112—if the condition has sharply worsened or signs of a life-threatening condition have appeared.
The material is for reference and does not replace a doctor's consultation: only a doctor can review your test results as a whole.
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This content is for reference and does not replace a doctor's consultation. Medical disclaimer