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  2. Hemoglobin


  1. What is hemoglobin and what is its function in the body?
  2. How are hemoglobin levels measured?
  3. Normal levels
  4. High levels
  5. Low levels
  6. Hemoglobin A1c test
  7. FAQs

What is hemoglobin and what is its function in the body?

Hemoglobin (Hb or Hgb) is a complex protein found in red blood cells. Its primary function is to help circulate oxygen around the body and transport carbon dioxide from tissues to the lungs. Hemoglobin contains iron, which helps give blood its red color.[1]

How are hemoglobin levels measured?

Hemoglobin is measured as part of a complete blood count (CBC), also called a full blood count (FBC) – a routine test that is commonly ordered by doctors to help diagnose a range of conditions, such as infection, anemia or leukemia.[2] To carry out a CBC, a blood sample will typically be taken from a vein in the arm.

Read more about Hemoglobin Levels »

Hemoglobinopathy evaluation (hemoglobin electrophoresis)

A hemoglobinopathy evaluation, otherwise known as a hemoglobin electrophoresis, may be ordered as a follow-up test to a CBC if an individual shows signs of atypically high or low levels of hemoglobin. The test is able to detect the presence of abnormal types of hemoglobin and measure their relative amounts in the blood.

There are many types of hemoglobin, the most common being HbA, HbA2, HbF, HbS, HbC, HbE, HbH and HbM. Healthy blood contains significant levels of HbA and HbA2 only. The detection of other types in significant quantities can signal the presence of a variety of conditions. HbS and HbC, for example, are associated with hemolytic anemia.

What are normal hemoglobin levels?

What is considered to be a normal hemoglobin range typically depends on sex, age and general health. Abnormally low or high levels of hemoglobin can indicate a range of health conditions, including anemia and sickle cell disease.

High hemoglobin levels

Having high levels of hemoglobin is rare in comparison to low levels. Typically, the disorder will be noticed as part of a routine blood test, and treatment will be aimed at the underlying cause of the condition in the majority of cases.[3] High hemoglobin levels can result from smoking, dehydration, emphysema, copd or other chronic lung conditions, chronic heart problems, some blood marrow disorders including polycythemia vera, and some kidney or liver cancers.

Living at high altitudes can also cause high hemoglobin levels as a natural adaptation mechanism to compensate for less oxygen in the air.

The symptoms of high hemoglobin levels may often be related to the underlying condition that is causing them. People experiencing possible symptoms of high hemoglobin levels can use the free Ada app to carry out a symptom assessment.

Read more about Hemoglobin Levels

Low hemoglobin levels (anemia)

A low hemoglobin count is commonly referred to as anemia.

Other conditions related to low hemoglobin levels include:

  • Sickle cell disease, a group of conditions that cause hemoglobin to be abnormally shaped and red blood cells to break down more easily than normal. Sickle cell disease is acquired genetically.
  • Thalassemia, a genetic disorder which impairs the function of hemoglobin in the body.

If you are experiencing symptoms that may be linked to anemia, try using the free Ada app for a symptom assessment.

Read more about Anemia »

Hemoglobin A1c test

The hemoglobin A1c test measures an individual's levels of blood glucose (blood sugar) over the previous three months, the typical lifespan of red blood cells. The test screens for hemoglobin A1c – also known as glycated hemoglobin or A1c – which is the product of glucose attaching to hemoglobin. This test is primarily used to diagnose, manage and research diabetes rather than to measure hemoglobin levels in general.[4][5]

Hemoglobin FAQs

Q: Can I raise my hemoglobin levels?
A: When anemia is caused by an iron deficiency, doctors may prescribe iron supplements to help boost red blood cell and hemoglobin production. It may also be advised to increase the amount of iron in one’s diet through consuming food such as:[6]

  • Leafy green vegetables, such as kale, swiss chard, spinach and watercress
  • Fortified cereals and breads
  • Brown rice and oats
  • Beans and pulses
  • Nuts and seeds
  • Meat, fish, tofu and tempeh
  • Eggs
  • Dried fruit

Q: What is hemoglobinuria?
A: Hemoglobinuria is a term used to describe the presence of hemoglobin in the urine. Typically, hemoglobin is not present in urine, so if hemoglobinuria occurs, it may be a sign of a medical condition in need of attention. Hemoglobinuria generally makes urine appear abnormally dark in color.[7]

Q: What is the relationship between hemoglobin and the hematocrit?
A: A complete blood count (CBC) measures several components of the blood, including the levels of hemoglobin and the volume of red blood cells as compared to the total volume of blood, a measure known as the hematocrit. As hemoglobin is contained within red blood cells, both counts tend to correspond with one another: if hemoglobin levels are high, it is likely that the hematocrit will be too, and vice versa. To learn more about how to interpret a CBC, take a look at this resource on blood tests results.

Q: Is there a link between hemoglobin and cancer?
A: Yes, some types of cancer can affect hemoglobin levels. For example, leukemia, lymphoma and other types of cancer that can induce blood loss, such as colon cancer, may lead to low levels, while others, including a kind of bone marrow cancer called polycythemia vera, can cause levels to rise. There is also a link between chemotherapy, a common cancer treatment, and low hemoglobin levels or anemia. Chemotherapy uses drugs administered intravenously, to destroy cancerous cells. In some cases, healthy red blood cells can be attacked by some of these drugs, leading to anemia. Read more about chemotherapy side-effects here.

Other names for hemoglobin

  • Haemoglobin
  • Hb
  • Hgb

  1. MedicineNet. “Hemoglobin.” April 11, 2015. Accessed November 6, 2017.

  2. National Heart, Lung, and Blood Institute. “Types of Blood Test.” January 6, 2012. Accessed November 6, 2017.

  3. Tandurust. “Causes of High Hemoglobin Levels: Symptoms & Treatment Options.” October 7, 2015. Accessed November 6, 2017.

  4. National Institute of Diabetes and Digestive and Kidney Diseases. “The AC1 Test and Diabetes.” September, 2014. Accessed November 6, 2017.

  5. Lab Tests Online. “Hemoglobin A1C.” September 4, 2015. Accessed November 6, 2017.

  6. Patient. “Anaemia.” November 1, 2017. Accessed November 6, 2017.

  7. MedicineNet. “Hemoglobinuria.” May 13, 2016. Accessed November 6, 2017.