Coombs Test Direct, EDTA Whole Blood

The Direct Coombs test (DCT) is performed to detect anti-D antibodies or other antibodies attached to the red cell surface within the blood stream. This occurs in the following circumstances. When there is an Rh positive baby in the womb of a sensitized Rh negative woman, the antibodies produced in the mothers serum cross the placenta and enter the babys blood stream. They attach to the babys Rh positive red blood cells. These coated red blood cells are agglutinated and removed from the circulation quickly resulting in hemolytic disease of the new born (Erythroblastosis fetalis). When the baby is born, the babys blood or cord blood is collected and tested by the Direct Coombs test (DCT) to detect anti-D anti-bodies which are coated on the red blood cells. Drug induced red cell sensitization, Auto immune hemolytic anemia, Malignant diseases, Infections like mycoplasma pneumonia and mononucleosis are also detected by Direct Coombs test (DCT). The Direct Coombs test (DCT) may also be used to investigate hemolytic reactions to blood transfusion. If a person develops fever or other significant symptoms post transfusion which suggest a hemolytic transfusion reaction, a Direct Coombs test (DCT) is done to determine if the person has developed antibodies to the transfused RBCs. If the antibody coats the transfused RBCs, then the RBCs may be destroyed (hemolyzed) or be removed from circulation quickly.

1. Can a person develop antibodies after blood donation?

No, a person will not be exposed to any antibodies after a blood donation.

2. If a mother has an incompatibility with one pregnancy, will she have them with other pregnancies as well?

No, not necessarily. It depends on the blood group of the fetus in the future pregnancies.

3. What is a Coombs test?

There are two types of coombs test - direct and indirect. The Direct Coombs test (DCT) is performed to detect anti-D antibodies or other antibodies attached to the red cell surface within the blood stream. This occurs in the following conditions like Rh incompatibility, infections, autoimmune diseases, drug induced, transfusion reactions, certain malignancies etc.

The indirect Coombs test is performed to detect the presence of Rh antibodies or other antibodies in the patient’s serum in the following cases - to check whether an Rh negative woman (married to Rh positive husband) has developed anti Rh antibodies, Anti D may be produced in the blood of any Rh negative person by exposure to D antigen by the following - transfusion of Rh positive blood, pregnancy, if the infant is Rh positive and after abortion of Rh positive fetus.