A Coombs test , also known as antiglobulin test AGT is either of two blood tests used in immunohematology. They are the direct and indirect Coombs tests. The direct Coombs test detects antibodies that are stuck to the surface of the red blood cells. The indirect Coombs detects antibodies that are floating freely in the blood.
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This condition is called anemia , and it has many causes. If your doctor confirms that you have a low red blood cell count, the Coombs test is one of the blood tests your doctor may order to help find out what kind of anemia you have.
The Coombs test checks the blood to see if it contains certain antibodies. Antibodies are proteins that your immune system makes when it detects that something may be harmful to your health. These antibodies will destroy the harmful invader. This can cause many kinds of health problems. The Coombs test will help your doctor determine if you have antibodies in your bloodstream that are causing your immune system to attack and destroy your own red blood cells.
If your red blood cells are being destroyed, this can result in a condition called hemolytic anemia. There are two types of Coombs tests: the direct Coombs test and the indirect Coombs test. The direct test is more common and checks for antibodies that are attached to the surface of your red blood cells. The indirect test checks for unattached antibodies that are floating in the bloodstream. A sample of your blood will be needed to perform the test.
The blood sample is obtained through venipuncture, in which a needle is inserted into a vein in your arm or hand. The needle draws a small amount of blood into tubing. The sample is stored in a test tube. This test is often done on infants who may have antibodies in their blood because their mother has a different blood type.
To do this test in an infant, the skin is pricked with a small sharp needle called a lancet, usually on the heel of the foot. Blood is collected into a small glass tube, on a glass slide, or on a test strip. No special preparation is necessary. Your doctor will have you drink a normal amount of water before going to the laboratory or collection site. You may have to stop taking certain medications before the test is performed, but only if your doctor tells you to do so.
When the blood is collected, you may feel moderate pain or a mild pinching sensation. However, this is usually for a very short time and very slight. After the needle is removed, you may feel a throbbing sensation. A bandage will be applied. You should avoid using that arm for heavy lifting for the rest of the day. A clumping of the red blood cells during the test indicates an abnormal result. Agglutination clumping of your blood cells during a direct Coombs test means that you have antibodies on the red blood cells and that you may have a condition that causes the destruction of red blood cells by your immune system, called hemolysis.
Drug toxicity is another possible condition that may cause you to have antibodies on red blood cells. Drugs that can lead to this include:. Sometimes, especially in older adults, a Coombs test will have an abnormal result even without any other disease or risk factors. An abnormal result in an indirect Coombs test means you have antibodies circulating in your bloodstream that could cause your immune system to react to any red blood cells that are considered foreign to the body — particularly those that may be present during a blood transfusion.
Depending on the age and circumstances, this could mean erythroblastosis fetalis, an incompatible blood match for a blood transfusion, or hemolytic anemia due to an autoimmune reaction or drug toxicity. Infants with erythroblastosis fetalis may have very high levels of bilirubin in their blood, which leads to jaundice.
This reaction occurs when the infant and mother have different blood types, such as Rh factor positive or negative or ABO type differences. This condition must be watched carefully. It can result in death of the mother and child.
A pregnant woman is often given an indirect Coombs test to check for antibodies before labor during prenatal care. Red blood cells carry oxygen from your lungs to your entire body. When dying red blood cells outpace the bone…. It occurs…. Leukemia is a cancer of the blood cells.
Get the statistics on survival rates, find out the most common symptoms, diagnostic options, and treatments. There are many ways to increase your red blood cell count, from dietary changes to supplements. Eating foods rich in iron, folic acid, and vitamin…. A transfusion reaction is when your body has an adverse response to a blood transfusion. A blood transfusion is a lifesaving procedure that adds…. Blood cell disorders impair the formation and function of red blood cells, white blood cells, or platelets.
The CBC is used to measure your general health. The test is usually part of a complete blood count…. Why is the Coombs test done? How is the Coombs test done? How do I prepare for the Coombs test? What are the risks of the Coombs test? What are the results for the Coombs test? Erythroblastosis Fetalis. Autoimmune Hemolytic Anemia.
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