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Serum hemoglobin is a blood test that measures the level of free hemoglobin in the liquid part of the blood (the serum). Free hemoglobin is the hemoglobin outside of the red blood cells. Most of the hemoglobin is found inside the red blood cells, not in the serum.
Blood hemoglobin; Serum hemoglobin
How the test is performed
A blood sample is needed. For information on how this is done, see: Venipuncture
How to prepare for the test
No preparation is necessary.
How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed
Hemoglobin (Hb) (the main component of red blood cells) is a protein that carries oxygen away from the lungs to the body tissues. This test is done to diagnose or monitor the severity of various kinds of hemolytic anemia -- a low red blood cell count caused by the abnormal breakdown of red blood cells.
- Females 12.3–15.3 g/dL
- Males 14.0–17.5 g/dL
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different samples.
Note: g/dL = grams per deciliter
What abnormal results mean
Elevated levels may indicate:
What the risks are
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Bunn HF. Approach to the anemias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 161.
Marks PW, Glader B. Approach to Anemia in the Adult and Child. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 34.
- Last reviewed on 2/8/2012
- Todd Gersten, MD, Hematology/Oncology, Palm Beach Cancer Institute, West Palm Beach, FL. Review provided by VeriMed Healthcare Network. Also reviewed by Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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