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Hemoglobin derivatives
Methemoglobin; Carboxyhemoglobin; Sulfhemoglobin
Hemoglobin derivatives are altered forms of hemoglobin . Hemoglobin is a protein in red blood cells that moves oxygen and carbon dioxide between the lungs and body tissues.
Hemoglobin
Hemoglobin is a protein in red blood cells that carries oxygen. The hemoglobin test measures how much hemoglobin is in your blood.
This article discusses the test used to detect and measure the amount of hemoglobin derivatives in your blood.
How the Test is Performed
The test is done using a small needle to collect a sample of blood from an artery. The sample may be collected from an artery in the wrist, groin, or arm.
Before blood is drawn, the health care provider may test circulation to the hand (if the wrist is the site). After the blood is drawn, pressure applied to the puncture site for a few minutes stops the bleeding.
How to Prepare for the Test
No special preparation is needed.
For children, it may help to explain how the test will feel and why it is done. This may make the child feel less nervous.
How the Test will Feel
You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.
Why the Test is Performed
This test is used to diagnose carbon monoxide poisoning . It is also used to detect changes in hemoglobin that may result from certain drugs. Some chemicals or drugs can change the hemoglobin so it no longer works properly.
Carbon monoxide poisoning
Carbon monoxide is an odorless gas that causes thousands of deaths each year in North America. Breathing in carbon monoxide is very dangerous. It i...
Abnormal forms of hemoglobin include:
- Carboxyhemoglobin: An abnormal form of hemoglobin that has attached to carbon monoxide instead of oxygen or carbon dioxide. High amounts of this type of abnormal hemoglobin prevent the normal movement of oxygen by the blood.
- Sulfhemoglobin: A rare abnormal form of hemoglobin that can't carry oxygen. It may result from certain medicines such as phenacetin, or sulfonamides.
- Methemoglobin: A problem that occurs when the iron that is part of hemoglobin is changed so that it does not carry oxygen well. Certain drugs and other compounds such as nitrites introduced into the blood stream can cause this problem.
Normal Results
The following values represent the percentage of hemoglobin derivatives based on total hemoglobin:
- Carboxyhemoglobin: less than 1.5% (but may be as high as 9% in smokers)
- Methemoglobin: less than 2%
- Sulfhemoglobin: undetectable
Normal value ranges may vary slightly among different laboratories. Talk to your provider 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 specimens.
What Abnormal Results Mean
High levels of hemoglobin derivatives can lead to major health problems. The altered forms of hemoglobin do not allow oxygen to be moved properly through the body. This can lead to tissue death.
The following values, except sulfhemoglobin, represent the percentage of hemoglobin derivatives based on total hemoglobin:
Carboxyhemoglobin:
- 10 to 20% - symptoms of carbon monoxide poisoning begin to appear
- 30% - severe carbon monoxide poisoning present
- 50 to 80% - results in potentially deadly carbon monoxide poisoning
Methemoglobin:
-
10 to 25% - results in bluish skin color (
cyanosis
)
Cyanosis
Cyanosis is a bluish color to the skin or mucous membrane that is usually due to a lack of oxygen in the blood.
ImageRead Article Now Book Mark Article - 35 to 40% - results in shortness of breath and headache
-
Over 60% - results in
lethargy
and
stupor
Lethargy
Fatigue is a feeling of weariness, tiredness, or lack of energy.
Read Article Now Book Mark ArticleStupor
Decreased alertness is a state of reduced awareness. A coma is a state of decreased alertness from which a person cannot be awakened. A long-term co...
Read Article Now Book Mark Article - Over 70% - may result in death
Sulfhemoglobin:
- Values of 10 grams per deciliter (g/dL) or 6.2 millimoles per liter (mmol/L) cause bluish skin color due to lack of oxygen (cyanosis), but do not cause harmful effects most of the time.
References
Benz EJ Jr, Ebert BL. Hemoglobin variants associated with hemolytic anemia, altered oxygen affinity, and methemoglobinemias. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, Anastasi J, eds. Hoffman Hematology: Basic Principles and Practice . 6th ed. Philadelphia, PA: Elsevier Churchill Livingstone ; 2013:chap 41.
Bunn HF. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 158.
Christiani DC. Physical and chemical injuries of the lung In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 94.
Nelson LS, Ford MD. Acute poisoning. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 110.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
-
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 4/30/2015
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
