Why coombs test

The test shows whether the mother has made antibodies and if the antibodies have moved through the placenta to her baby. The indirect Coombs test finds certain antibodies that are in the liquid part of your blood serum. These antibodies can attack red blood cells but are not attached to your red blood cells. The indirect Coombs test is commonly done to find antibodies in a recipient's or donor's blood before a transfusion. A test to determine whether a woman has Rh-positive or Rh-negative blood Rh antibody titer is done early in pregnancy.

If she is Rh-negative, steps can be taken to protect the baby. When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch. There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site. A negative test result means that your blood does not have antibodies attached to your red blood cells.

A negative test result means that your blood is compatible with the blood you are to receive by transfusion. A negative indirect Coombs test for Rh factor Rh antibody titer in a pregnant woman means that she has not developed antibodies against the Rh-positive blood of her baby.

This means that Rh sensitization has not occurred. A positive result means that your blood has antibodies that fight against red blood cells. This can be caused by a transfusion of incompatible blood. Or it may be related to conditions such as hemolytic anemia or hemolytic disease of the newborn HDN. A positive test result means that your blood is incompatible with the donor's blood and you can't receive blood from that person. If the Rh antibody titer test is positive in a woman who is pregnant or is planning to become pregnant, it means that she has antibodies against Rh-positive blood Rh sensitization.

She will be tested early in pregnancy to check the blood type of her baby. If the baby has Rh-positive blood, the mother will be watched closely throughout the pregnancy to prevent problems to the baby's red blood cells. If sensitization has not occurred, it can be prevented by a shot of Rh immunoglobulin. Current as of: September 23, Gabica MD - Family Medicine. Author: Healthwise Staff. Medical Review: E. This information does not replace the advice of a doctor. 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…. Leukemia is a cancer of the blood cells. Get the statistics on survival rates and find out the most common symptoms, diagnostic options, and….

Has your doctor advised you to increase your red blood cell count? These supplements and lifestyle changes may help.

A transfusion reaction is when your body has an adverse response to a blood transfusion. Learn how transfusion reactions occur and how to minimize…. Blood cell disorders impair the formation and function of red blood cells, white blood cells, or platelets. The test is usually part of a complete blood count…. Health Conditions Discover Plan Connect. Why is the Coombs test done? How is the Coombs test done?

This is the test that is done on the newborn's blood sample, usually in the setting of a newborn with jaundice. The test is looking for "foreign" antibodies that are already adhered to the infant's red blood cells rbcs , a potential cause of hemolysis.

This is referred to as "antibody-mediated hemolysis". The two most commonly recognized forms of antibody-mediated hemolysis in newborns are Rh incompatibility and ABO incompatibility. ABO incompatibility occurs by the same general mechanism. Type O mothers are most commonly impacted, since they carry both anti-A and anti-B antibodies.

If the infant is type A, type B, or type AB, risk for incompatibility exists. This is frequently referred to as a "set-up". If mixing of maternal and fetal blood occurs during pregnancy or the birth process, these antibodies can also attack the baby's rbcs and cause hemolysis.