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Hemoglobin Blood Test

Last updated Sept. 3, 2018

Approved by: Krish Tangella MD, MBA, FCAP

The Hemoglobin Blood Test is done to measure the amount of hemoglobin present in blood.


What are the other Names for this Test? (Equivalent Terms)

  • Hb Test
  • Hgb Test

What is Hemoglobin Blood Test? (Background Information)

  • Red blood cells (RBCs) contain a protein, called hemoglobin, which helps in carrying oxygen from the lungs, to the rest of the body tissue. It is responsible for the color of the RBCs
  • The Hemoglobin Blood Test is done to measure the amount of hemoglobin present in blood
  • The test may be ordered alone, or more commonly, as part of a complete blood count (CBC) and is performed during a general health evaluation, or to diagnose, evaluate, and monitor conditions, such as anemia (low hemoglobin in blood) or polycythemia (a disorder with increased RBC numbers)

What are the Clinical Indications for performing the Hemoglobin Blood Test?

Following are the clinical indications for performing a Hemoglobin Blood Test:

  • As part of a general health investigation
  • To screen for, diagnose, and monitor anemia: The severity of anemia and the mode of treatment are also decided, based on hemoglobin levels. Anemia may present with symptoms, such as:
    • Pallor of eyes/nail beds/palm of hand/tongue
    • Fatigue and lethargy
    • Fast heartbeat, breathlessness
  • To diagnose or monitor polycythemia, a condition with increased RBC numbers. Symptoms of polycythemia include:
    • Headache
    • Flushed appearance
    • Dizziness
    • Vision disturbances

How is the Specimen Collected for Hemoglobin Blood Test?

Following is the specimen collection process for Hemoglobin Blood Test:

Sample required: Blood

Process:

  • Blood sample is drawn through a needle inserted into the vein (arm). The sample may also be obtained by making a finger prick
  • In newborns, the blood sample is drawn from the heel after making a small nick using a scalpel. This is called a heel stick

Preparation required: No special preparation is needed prior to the test.

What is the Significance of the Hemoglobin Blood Test Result?

The normal values, called the reference range for hemoglobin, may vary slightly from lab to lab. Hence, most lab reports come with a reference range, which is used in that particular centre. A physician interprets the results based on the reference values provided.

A standard reference range in wide use is:

  • Male: 13.8-17.2 gm/dL (grams per deciliter)
  • Female: 12.1-15.1 gm/dL

Some conditions that may lead to decreased levels of hemoglobin include:

  • Decreased production of red blood cells, due to longstanding kidney disease or bone marrow disorders, such as aplastic anemia, blood cancers, or bone marrow damage, mediated by infections, toxins, etc.
  • Nutritional deficiencies, such as deficiencies of iron, folate, or vitamin B12
  • Increased destruction of red blood cells
  • Excessive bleeding

Some conditions that may lead to increased levels of hemoglobin include:

  • Polycythemia vera - a condition, where the body produces an increased numbers of red blood cells
  • Congenital heart disease (in which blood from the two sides of the heart mix with each other, via an abnormal connection)
  • Longstanding lung diseases
  • Dehydration
  • Living in high altitudes

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

References and Information Sources used for the Article:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: June 12, 2014
Last updated: Sept. 3, 2018