Usually, antibodies attach to foreign items like viruses and bacteria, and kill them. The following disorders result in antibodies to be constructed.
Blood Transfusion Reactions and Antibody Tests
Human blood is classified by specific markers (known as antigens) on the outer edge of red blood cells. When a person receives a transfusion, the transfused blood should match the patient's type; in other words, it should carry the same antigens as the erythrocytes (red blood cells).
When a person undergoes a blood transfusion of blood with antigens unlike the donor's (incompatible blood cells), the immune system destroys the new blood cells. This is referred to as a transfusion response and may bring about intense sickness or possibly death. This is basically why matching blood group is so crucial.
Rh Sensitization and Antibody Tests
Rh is an antigen. The formal term for this antigen is Rh factor.
When a pregnant individual with Rh-negative blood type delivers a baby with Rh-positive blood cells, Rh sensitization can take place. The baby acquires Rh-positive blood cells arising from the father's genes. Rh sensitization takes place as the child's blood cells mixes with the parent's blood at the time of birth.
This makes the mother's immune complex produce antibodies against the child's RBCs in future pregnancies (gestations). This antibody reaction is known as Rh sensitization and, depending on when it occurs, may kill the fetal erythrocytes.
When sensitization occurs, the fetus can build up minor to extreme reactions (termed Rh (rhesus) disease, hemolytic illness of the newborn, or erythroblastosis fetalis. In unusual instances, when Rh sensitization is not addressed, the fetus may be killed as a result.
A mother with Rh-negative blood cells may receive a vaccine known as Rh immune globulin (like RhoGAM) that usually terminates sensitization from happening. Issues from Rh sensitization are extremely uncommon because the Rh immune globulin vaccine has been formulated.
Direct Coombs Antibody Test
The direct Coombs test looks for antibodies attached to the patient's own erythrocytes. These antibodies can be those the patient's body produced from illness or those a person gets from a transfusion.
The direct Coombs screening also may be completed on a newborn whose female parent consumes Rh-negative blood. The procedure depicts whether the adult has produced antibodies and if the antibodies have traveled through the placenta to her child.
Indirect Coombs Antibody Test
The indirect Coombs test looks for antibodies that are in the bloodstream but not bonded to the erythrocytes. The indirect Coombs test is generally carried out to observe antibodies in the recipient's or donor's blood prior to a blood transfusion.
An Rh antibody titer, is performed early in pregnancy to evaluate a female patient's blood type. If she is Rh-negative, measures can be taken to help the fetus.
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References:
Chernecky CC, and Berger BJ. (2004). "Laboratory Tests and Diagnostic Procedures" (4). Philadelphia: Saunders.
Pagana KD, and Pagana TJ. (2006). "Mosby’s Manual of Diagnostic and Laboratory Tests." (3). St. Louis: Mosby.
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