Hemoglobin
At a Glance
Why Get Tested?
If you have anemia or polycythemia, to assess the severity of these conditions, and to monitor response to treatment
When to Get Tested?
Usually, as part of a complete blood count (CBC), which may be ordered for a variety of reasons
Sample Required?
A blood sample drawn from a vein in your arm or by a fingerstick (children and adults) or heelstick (newborns)
Test Preparation Needed?
None
The Test Sample
What is being tested?
This test measures the amount of hemoglobin, a protein found in red blood cells, in a blood sample, which is a good indication of the blood’s ability to deliver oxygen to tissues and organs and to transport the waste product carbon dioxide to the lungs, where it is exhaled. If your hemoglobin levels are low, you may have anemia, a condition in which your body is not getting enough oxygen, causing fatigue and weakness.
The hemoglobin rises when the number of red blood cells increases. The hemoglobin falls to less than normal, indicating anemia, when your body decreases its production of red blood cells, increases its destruction of red blood cells, or if blood is lost due to bleeding.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in your arm or by a fingerstick (for children and adults) or heelstick (for newborns).
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
The Test
Common Questions
Ask a Laboratory Scientist
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Article Sources
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
S1
Thomas, Clayton L., Editor (1997). Tabers Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
S2
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosbys Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
S3
Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 524-527.
