The Indirect Coombs test is a blood test that is used to detect the presence of antibodies in the blood that can react with red blood cells. Unlike the Direct Coombs test, which tests for antibodies that are already attached to red blood cells, the Indirect Coombs test detects antibodies that are floating freely in the blood. The test is commonly used during pregnancy to determine if a woman has developed antibodies to the blood of her fetus. The test involves taking a blood sample from the mother and mixing it with a sample of the father’s blood to see if any antibodies are present. If antibodies are detected, it indicates that the mother’s immune system is producing antibodies against the fetus’s blood type, which can lead to hemolytic disease of the newborn. The Indirect Coombs test can also be used to screen blood donors for the presence of antibodies that can cause transfusion reactions. The test is an important tool in preventing and managing hemolytic diseases and other blood-related disorders.