An integral part of our immune system are antibodies. They aid in defending our bodies against infections, but occasionally they could target the body's healthy cells. Because each red blood cell in the body is unique, the immune system may create antibodies to fight against those that don't match the others. However, it can lead to a number of health issues if the immune system misinterprets the infection and begins to produce antibodies against the host's cells. Antibodies that could assault red blood cells are found using the Coombs test. The Coombs test could assist the physician in determining whether the immune system's generated antibodies are attacking and damaging the patient's red blood cells. Hemolytic anemia is the term used to describe this type of autoimmune destruction of red blood cells. The Direct Coombs Test is the more sensitive of the two Coombs tests for identifying antibodies bound to red blood cells. The Direct Coombs Test, also called the Direct Agglutination Test, is performed more frequently. This is because the red blood cells with the associated antibodies adhere to one another when exposed to the reagent used in the Coombs test. A Direct Coombs Test can also be done to diagnose transfusion reactions and fatal conditions like erythroblastosis fetalis. Other Names of Direct Coombs Test Direct antiglobulin test Coombs test Direct anti-human globulin test What does the test detect/measure and who is this prescribed for? The Direct Coombs test helps to diagnose hemolytic conditions. A Direct Coombs test is done to detect: Autoimmune diseases Hemolysis can take place in autoimmune conditions. A positive Direct Coombs test can be expected in: Autoimmune hemolytic anaemia: A condition in which the immune system attacks its own red blood cells in the body. Malignancies like leukaemia. Autoimmune diseases like systemic lupus erythematosus and antiphospholipid syndrome. Transfusion reaction Immediately after transfusion, the immune system may attack the donated blood cells. This usually occurs when the blood donor type is not an appropriate match. This can show up as early as two days after the transfusion. The recipient may experience symptoms like dizziness, back pain, dark urine and shortness of breath. Erythroblastosis fetalis Erythroblastosis fetalis is a fatal condition in which the fetus and the parents have different blood types. The difference may be in the Rh factor or ABO blood type. As a result, the immune system of the mother may attack the red blood cells of the infant, which can result in their death. In addition, infants with erythroblastosis fetalis may develop jaundice due to their high bilirubin levels. Infection Certain infections like syphilis, mononucleosis, malaria and AIDS can cause hemolysis. This can be detected through the Direct Coombs test. Adverse reactions to some medicines Certain medicines like cephalosporins (antibiotics), dapsone (antibacterial) and painkillers like ibuprofen can cause the destruction of red blood cells.

Hemolytic anaemia, erythroblastosis fetalis, transfusion-related hemolysis, autoimmune diseases, adverse reactions to some medicines

The Direct Coombs test is used to detect the coating of red blood cells with IgG antibodies and complements like C3d. Normal findings: Negative, no agglutination.

The Coombs test detects the agglutination or formation of clumps of red blood cells. The test is said to be negative when no clump is formed. A negative test usually indicates that antibodies are not attached to the red blood cells. This also signifies that the symptoms you are experiencing are probably due to another cause. A positive Direct Coombs test result means that agglutination occurs and antibodies are attached to the red blood cells. Thus, the immune system plays a significant role in destroying red blood cells. However, a positive Direct Coombs test does not always mean that hemolysis occurs. If hemolysis is suspected, a Direct Coombs test can be done to confirm the provisional diagnosis.

Typically, a Direct Coombs test requires a blood sample to be performed. A venipuncture is typically used to draw blood from a vein. Babies can also be used for this examination. This test involves pricking the skin, generally on the heel of the foot, with a needle. Typically, a test strip, slide, or tiny glass tube is used to collect the blood. Test Preparation Your doctor may suggest that you cease taking specific medications even though there are no safety measures performed before to the Direct Coombs test. Before visiting the lab or the collecting location, you are welcome to have some water. A needle will be used by your healthcare practitioner to draw blood from your arms. During the blood collection procedure, you can feel some minor discomfort. It normally has a modest intensity and lasts for a very brief time. You can get a throbbing feeling once the needle is taken out. It could be necessary for you to apply pressure to the needle's insertion location. Usually, a bandage is applied to the area for ten to twenty minutes. You should refrain from performing any intense exercise or lifting large weights with your arms raised. Before the test starts, the sample is gathered and kept in a container that prevents it from coagulating. After that, it is delivered to the lab for examination. It's not a dangerous test. On rare occasions, it may result in dizziness and fainting. At the location where the needle was inserted, it may result in infection. Moreover, bleeding may happen where the injection was made. A bleeding disorder should be reported to the doctor if there is excessive bleeding or bleeding that persists for an extended period of time. What parameters are included in the test? Antibodies against the RBC membrane: IgM and IgG