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What is a Hemoglobin Test?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

A hemoglobin test is a blood test which is used to determine how much hemoglobin a patient has in his or her body. This test is usually performed as part of a complete blood count, a routine screening which checks on the levels of a number of blood components. Levels of hemoglobin which differ from the norm can be indicative of a wide variety of health problems, and this test can be a very useful diagnostic tool. Additionally, people may utilize hemoglobin tests to monitor the progress of various medical conditions, such as anemia.

Hemoglobin is a protein which is found naturally in the blood. It performs a number of functions, but one of the most important is the transport of oxygen throughout the body. In adults, the hemoglobin level ranges between 12 and 18 grams per decaliter, with levels being lower in pregnant women. Children tend to have between 11 and 16 grams per decaliter. It is possible for a hemoglobin test to reveal numbers which may be higher or lower than the norm.

A blood test that measures the amount of hemoglobin in the body is known as a hemoglobin test.
A blood test that measures the amount of hemoglobin in the body is known as a hemoglobin test.

Low levels on a hemoglobin test can indicate the presence of problems like anemia and malnutrition, while high levels are associated with things such as dehydration and heart disease. It is also possible to perform tests on the hemoglobin itself to learn more about the condition of the patient. A glycated hemoglobin or A1c test, for example, checks for the amount of glucose in the blood, an indicator of poorly managed diabetes or of increased risk of developing diabetes.

Hemoglobin tests are usually part of a routine blood count.
Hemoglobin tests are usually part of a routine blood count.

To perform a hemoglobin test, a blood sample is drawn from a patient and put through a centrifuge to separate the primary components of the blood so that they can be analyzed the tested. Multiple vials of blood may be taken if several tests have been ordered, so that only one needle-stick is needed to gather all of the samples. Once the blood has been analyzed, a printed report is prepared for a physician so that he or she can utilize the information to evaluate a patient's condition and develop a treatment plan.

The hemoglobin test looks for levels of a protein that is important in the transport of oxygen throughout the body.
The hemoglobin test looks for levels of a protein that is important in the transport of oxygen throughout the body.

A number of things can alter hemoglobin levels. The levels tend to change throughout the day, for example, which is an important consideration if someone has an unusually low or high number, but feels otherwise healthy. By interviewing the patient before ordering the test, a doctor can get an idea of the patient's general condition, and use this information to evaluate the results of a hemoglobin test.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a TheHealthBoard researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a TheHealthBoard researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon139953

It's the other way round. Hematocrit is three times the Hemoglobin. So 12*3= 36

bythesea

My recent Blood Test showed my RBC's at 3.98 Hemoglobin at 12 and my Hematocrit at 33. I am confused because I thought that the Hemoglobin was 3 times the Hematocrit. I have vonWillebrand type 1, a prosthetic mitral valve and an aortic coarctation, could this influence my results?

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    • A blood test that measures the amount of hemoglobin in the body is known as a hemoglobin test.
      By: Kasia Bialasiewicz
      A blood test that measures the amount of hemoglobin in the body is known as a hemoglobin test.
    • Hemoglobin tests are usually part of a routine blood count.
      By: Nenov Brothers
      Hemoglobin tests are usually part of a routine blood count.
    • The hemoglobin test looks for levels of a protein that is important in the transport of oxygen throughout the body.
      By: weim
      The hemoglobin test looks for levels of a protein that is important in the transport of oxygen throughout the body.