Last Updated on April 7, 2025 by Analgesia team
What Level of Hemoglobin is Dangerously High
Hb is the medical abbreviation for hemoglobin, a protein in red blood cells that carries oxygen throughout the body. A hemoglobin test measures the amount of hemoglobin in your blood, which can indicate the health of your red blood cells. Abnormal hemoglobin levels may indicate a blood disorder.
- Less than 13.2 grams of hemoglobin per deciliter (132 grams per liter) of blood for men
- Less than 11.6 grams per deciliter (116 grams per liter) for women
A high hemoglobin count indicates an above-normal level of hemoglobin in your blood.
Hemoglobin levels above 20 grams per deciliter (g/dL) can be dangerous and lead to blood clots.
| Group | Normal Hb Range (g/dL) |
|---|---|
| Adult men | 13.8 – 17.2 |
| Adult women | 12.1 – 15.1 |
| Children (varies) | 11 – 16 |
| Pregnant women | 11 – 12 |
Note: Ranges can vary slightly by lab.
What does it mean if Hb is low?
Low hemoglobin (anemia) might mean:
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Iron deficiency
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Blood loss (e.g., from injury, menstruation, ulcers)
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Chronic diseases (kidney, cancer)
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Nutritional deficiencies (B12, folate)
- Hemoglobin levels above 20 g/dL can lead to blood clots.
- A high hemoglobin count is also known as polycythemia.
- Causes of high hemoglobin include smoking, testosterone supplementation, lung problems, kidney problems, and blood cancers.
- Hemoglobin levels that are too low can lead to heart failure and death.
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- Not making enough red blood cells
- Losing red blood cells faster than the body can replace them
- Low dietary iron or impaired iron absorption
- Menstrual bleeding
- Cancer, especially leukaemia
- Chemotherapy
- Blood loss from surgery, trauma, or an ulcer
- Autoimmune disorders, including lupus and certain thyroid conditions
- Chest pain
- Cold hands and feet
- Dizziness
- Fatigue
- Headaches
- Irregular heartbeat
- Paler-than-usual skin
- Shortness of breath
- Weakness
In sickle cell disease, a mutation in the haemoglobin beta gene (HBB) causes the production of abnormal haemoglobin, called haemoglobin S (HbS). This abnormal haemoglobin causes red blood cells to become rigid and sickle-shaped, which can block blood flow and lead to serious complications:
- Pain crises: Sudden and severe episodes of pain that can last for several hours or days
- Anaemia: A low red blood cell count that can cause fatigue
- Stroke: A serious complication that can occur in people with sickle cell disease.
- Acute chest syndrome: A condition that lowers the level of oxygen in the blood.
- Organ damage: Sickled cells can block blood flow to organs, causing damage.
How to Raise Hemoglobin Levels
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Popular natural remedies:
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Iron-rich foods (spinach, red meat, lentils)
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Iron supplements
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Vitamin C for better iron absorption