The Direct Coombs Test is a medical test used to detect and diagnose autoimmune hemolytic anemia, a condition in which the body's immune system mistakenly attacks and destroys healthy red blood cells. The test is also used to detect antibodies against red blood cells, which can be present in certain medical conditions. The test is relatively simple and can be performed in a laboratory setting.
Preparation
Prior to performing the Direct Coombs Test, a healthcare provider will collect a sample of the patient's blood. The sample will be placed in an anticoagulant, such as EDTA or heparin, to prevent the sample from clotting. It is important that the sample be kept at a consistent temperature to prevent the sample from degrading.
Procedure
The Direct Coombs Test is a two-step process. First, the sample is treated with an antibody called an "anti-human globulin". This antibody binds to any antibodies present in the sample, such as those that may be present due to an autoimmune disorder. The sample is then treated with a red blood cell that has been labeled with a fluorescent dye. If the antibodies present in the sample bind to the labeled red blood cell, the sample will light up under a microscope.
Results
If the sample lights up under the microscope, it is considered a positive result, indicating that the patient has an autoimmune disorder or has antibodies present in their blood. If the sample does not light up, it is considered a negative result, indicating that no antibodies are present.
Risks
The Direct Coombs Test is a relatively safe procedure and poses few risks to the patient. The only risks associated with the procedure are those associated with the blood draw, such as infection, bruising, or dizziness.
