Description

A DCT, or Direct Coombs Test (direct antiglobulin test), is a blood test that checks for antibodies or complement proteins stuck to the surface of your red blood cells (RBCs), which can destroy them and cause hemolytic anemia. A positive DCT indicates that your immune system is attacking its own RBCs, or that a reaction is occurring with antibodies from another source, such as a transfusion. The test is performed on a blood sample and requires no special preparation. What the DCT Detects Antibodies: Proteins that can target and destroy red blood cells. Complement proteins: Substances that can also attach to RBCs and contribute to their destruction. Why a DCT is Performed The test helps diagnose conditions where the body's immune system mistakenly attacks and destroys its own red blood cells. It is also used to identify transfusion reactions. Conditions the DCT is used to diagnose: Autoimmune Hemolytic Anemia (AIHA): A condition where the body's immune system attacks and destroys its own RBCs. Transfusion Reactions: To determine if a person has developed antibodies that are reacting to transfused blood. Hemolytic disease of the newborn: To check for the presence of maternal antibodies in a newborn's blood that can attack the baby's RBCs. How the DCT is Performed A blood sample is taken from the patient's arm. The blood sample is analyzed in a lab to check for antibodies or complement proteins attached to the RBCs. Results Positive Result: Indicates the presence of antibodies or complement proteins on the surface of the RBCs. Negative Result: Means that no antibodies or complement proteins were found attached to the RBCs. What a Positive Result Means A positive DCT indicates that the immune system is likely responsible for destroying red blood cells, leading to a condition like autoimmune hemolytic anemia. It can also point to a transfusion reaction.