What is a Coombs Test?
A Coombs test examines the blood for antibodies that can damage the red blood cells. Antibodies play an important role in the immune system. They fight off antigens (such as bacteria, viruses, and other toxins) to keep you healthy. Yet antibodies can sometimes damage normal, healthy cells by mistake.
What is the purpose of the Coombs test?
To begin, it's essential to recognize that there are two types of Coombs tests: direct and indirect.
- The direct Coombs test (also known as a direct antiglobulin test) examines the red blood cells to check if they have antibodies attached to them. It is frequently used to diagnose blood-related disorders such as autoimmune hemolytic anemia. Individuals who suffer from autoimmune hemolytic anemia do not have enough red blood cells because their bodies destroy them too quickly.
- The indirect Coombs test shows the doctor if antibodies in the circulation are capable of attaching to red blood cells. It is used to determine how you will react to a blood transfusion. In addition, an indirect Coombs test is commonly given as part of prenatal testing.
How should I prepare for a Coombs test?
In general, there is no specific preparation required for a Coombs test. However, you should inform your healthcare provider of any medications, supplements, or herbal remedies you are taking, as these may interfere with the test results. It is also important to let your healthcare provider know if you have had a blood transfusion in the past, as this may affect the test results.
One may be asked to fast for a certain time before the test. In this case, the healthcare provider will provide you with specific instructions regarding fasting.
It is also important to let your healthcare provider know if you have a history of bleeding or bruising easily or if you are taking any medications that affect blood clotting, as the Coombs test involves drawing blood.
It is recommended to wear comfortable clothing that allows easy access to the arm for a blood draw during the test.
What can I expect during the test?
A tiny needle is used by the healthcare provider to draw a blood sample from a vein in the arm or hand. After the sample is taken, it is submitted to a lab for analysis. The provider will apply a bandage to the site where the needle was inserted. After 10 to 20 minutes, the bandage can be removed.
When should I expect to receive the test results?
In most cases, the test results will be available within 24 hours.
What does a positive Coombs test mean?
A positive (abnormal) Coombs test indicates the presence of antibodies capable of attacking red blood cells. Several conditions can cause this, including:
When should I call my healthcare provider?
Call the physician immediately if you experience any hemolytic anemia symptoms like jaundice, weakness, lightheadedness, or confusion. They can conduct an examination and do tests to choose the best course of action.