Blood test

Low hemoglobin level in the blood

Blood test
Low hemoglobin level in the blood

What is low total hemoglobin level in the blood called?

  • Anemia

What is the normal hemoglobin level in the blood?

If you need to know which are the hemoglobin reference ranges or you require more information about the role of hemoglobin in the blood you can visit: Normal hemoglobin level in the blood

What does a low total hemoglobin level in the blood mean?

A low level of hemoglobin in the blood is referred as anemia. Anemia is defined as a reduction in the concentration of hemoglobin in the blood below the normal range for the age and sex of the patient.

Signs and symptoms of anemia may include pallor of the skin, shortness of breath, palpitations of the heart, lethargy, and fatigability.

WHO (World Health organization) considers the existence of anemia when the hemoglobin level is below 13 g/dl in men, 12 g/dl in women and 11 g/dl in pregnant women.

Anemia is a group of disorders with multiple causes. The most common type is iron-deficiency anemia, but there is a lot of type depending on the origin:

  • Iron-deficiency anemia: It is a consequence of iron deficit and it is the most common. The lack of iron may be due blood loss (menstruation, bleeding, ulcer, etc.) or due to iron deficiency in the diet.
  • Hemolytic anemia: Due to a genetic disorder the RBCs (Red Blood cell) are destroyed faster than they can be made.
  • Megaloblastic anemia: Lack of vitamin B12 or folic acid.
  • Chronic disease anemia: Kidney disorders (kidney failure) or liver disorders (cirrhosis, hepatitis C, etc.) may reduce the hemoglobin in the blood.
  • Aplastic anemia: The bone marrow is damaged and it fails to produce enough blood cells.

The presence of a low level of hemoglobin in a blood test is the starting point to study the type of anemia that may be present. In any case, sometimes it is necessary to prescribe a treatment to for the symptoms related.

Hemoglobin values are usually given in g/dl but sometimes you can see these values in mmol/l following the International System of Units (SI). In case your values are in mmol/l, you can convert them using this tool:


Anemia or a low hemoglobin level in the blood means:

  • Mild anemia (11 - 12 g/dl in adult women and 11 - 13 g/dl in adult men):

    The hemoglobin level in the blood is a bit high. You may be suffering irritability, headache, fatigue and shortness of breath.

    You should ask an appointment with your doctor. He will review your diet, the possible existence of a bleeding or the interference of drugs that may affect your hemoglobin level in the blood. He will decide the proper treatment for you.

  • Moderate anemia (8 - 11 g/dl in adult women and 8 - 11 g/dl in adult men):

    In case of moderate anemia, you may have pale skin and suffer from dizziness, fainting and palpitations. Besides, you need a lot of effort to do common physical activities such as walking fast or go upstairs. Even you may feel pain if you walk too much time.

    This situation needs a visit to your doctor who will prescribe you the proper treatment.

  • Severe anemia (< 8 g/dl in adult women and < 8 g/dl in adult men):

    A severe anemia is a serious health problem and you should look for immediate health assistance.

    If the hemoglobin level is extremely low, you will not be able to perform any physical activity and it may lead to a heart failure.

    It is urgent to increase the hemoglobin level in the blood and if the hemoglobin level is below 6 g/dl it is usually necessary to administer a blood transfusion.

Which factors can reduce the hemoglobin level in the blood?

There are some health circumstances or drugs than can reduce your hemoglobin level in the blood:

  • Alcohol
  • Pregnancy
  • Bleeding
  • Malnutrition
  • Intermenstrual bleeding
  • Drugs
    • Nonsteroidal anti-inflammatory drugs (NSAIDs)
      • Diclofenac
    • Aniline
    • Antineoplastics
      • Methotrexate
    • Antituberculars
      • Rifampicin
    • Bacteriostatic agent
      • Chloramphenicol
    • Diuretics
      • Chlorothiazide
    • ACE inhibitor
      • Captopril
      • Enalapril

Which diseases can reduce your hemoglobin level in the blood?

Lower than normal level of hemoglobin in the blood can be due to:

  • Iron-deficiency anemia
  • Megaloblastic anemia
  • Hemolytic anemia
  • Thalassemia
  • Sideroblastic anemia
  • Aplastic anemia
  • Hereditary spherocytosis
  • Elliptocytosis
  • Sickle cell disease
  • Paroxysmal nocturnal hemoglobinuria
  • Fanconi anemia
  • Kidney failure
  • Lymphoma
  • Leukemia
  • Multiple myeloma
  • Hypothyroidism
  • Malaria
  • Hepatic cirrhosis
  • Hepatitis
  • Scurvy
  • Gaucher's disease

What can I do to increase the hemoglobin level in the blood?

The causes that may trigger the anemia are multiples. For that reason, the main goal is to know the type of anemia that is present to prescribe a better treatment.

However, in general, you may follow the next tips:

  • Reduce or avoid alcohol.
  • Follow a healthy diet with an appropriate intake of iron, vitamin B 12, folic acid and copper that are essential in the hemoglobin production.
  • If the anemia is due to blood loss (menstruation, bleeding, ulcer, etc.) it is probable that you suffer from iron-deficiency anemia that it is the most common. In that case, you should increase the iron intake and if your doctor considers it appropriate, you may require iron supplements.

Where can I find more information about hemoglobin level in the blood?

You can visit our pages about:

Which values are considered a low hemoglobin level in the blood?

The following values are considered to be above the normal range:

IMPORTANT: These levels are expressed in gr/dl. They are an example of a healthy woman of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.

Mild anemia
11.9 g/dl11.8 g/dl11.7 g/dl11.6 g/dl11.5 g/dl11.4 g/dl11.3 g/dl11.2 g/dl
11.1 g/dl11 g/dl      
Moderate anemia
10.9 g/dl10.8 g/dl10.7 g/dl10.6 g/dl10.5 g/dl10.4 g/dl10.3 g/dl10.2 g/dl
10.1 g/dl10 g/dl9.9 g/dl9.8 g/dl9.7 g/dl9.6 g/dl9.5 g/dl9.4 g/dl
9.3 g/dl9.2 g/dl9.1 g/dl9 g/dl8.9 g/dl8.8 g/dl8.7 g/dl8.6 g/dl
8.5 g/dl8.4 g/dl8.3 g/dl8.2 g/dl8.1 g/dl8 g/dl  
Severe anemia
7.9 g/dl7.8 g/dl7.7 g/dl7.6 g/dl7.5 g/dl7.4 g/dl7.3 g/dl7.2 g/dl
7.1 g/dl7 g/dl6.9 g/dl6.8 g/dl6.7 g/dl6.6 g/dl6.5 g/dl6.4 g/dl
6.3 g/dl6.2 g/dl6.1 g/dl6 g/dl5.9 g/dl5.8 g/dl5.7 g/dl5.6 g/dl
5.5 g/dl5.4 g/dl5.3 g/dl5.2 g/dl5.1 g/dl5 g/dl4.9 g/dl4.8 g/dl
4.7 g/dl4.6 g/dl4.5 g/dl4.4 g/dl4.3 g/dl4.2 g/dl4.1 g/dl4 g/dl
3.9 g/dl3.8 g/dl3.7 g/dl3.6 g/dl3.5 g/dl3.4 g/dl3.3 g/dl3.2 g/dl
3.1 g/dl3 g/dl2.9 g/dl2.8 g/dl2.7 g/dl2.6 g/dl2.5 g/dl2.4 g/dl
2.3 g/dl2.2 g/dl2.1 g/dl2 g/dl    
Last update: 09/12/2020


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