Antihuman globulin test (Coombs test); indirect, qualitative, each reagent red cell
CPT4 code
Name of the Procedure:
Antihuman Globulin Test (Coombs Test); Indirect, Qualitative, Each Reagent Red Cell.
Summary
The Antihuman Globulin Test, commonly known as the Coombs Test, is a blood test used to detect antibodies that can bind to the surface of red blood cells. The indirect version of this test checks for these antibodies in a patient’s serum using reagent red cells.
Purpose
The test is designed to detect potential antibodies in the blood that could lead to complications such as hemolytic anemia or hemolytic reactions during blood transfusions. It is also used in prenatal testing to identify Rh incompatibility between a pregnant woman and her unborn child.
Indications
- Unexplained hemolytic anemia
- Preparing for a blood transfusion
- Pregnancy, particularly in those at risk of Rh incompatibility
- Monitoring of certain autoimmune diseases
- Organ transplant preparation
Preparation
The patient generally does not need to perform any special preparations. However, it is important to inform the healthcare provider of any medications being taken, as some drugs can affect the test results.
Procedure Description
- Blood Sample Collection: A healthcare professional draws a small amount of blood from the patient's vein into a test tube.
- Serum Separation: The blood sample is processed to separate the serum from the red blood cells.
- Mixing with Reagent Red Cells: The patient's serum is then mixed with reagent red cells.
- Addition of Antihuman Globulin: Antihuman globulin (Coombs reagent) is added to this mixture.
- Observation: The mixture is observed for agglutination (clumping of cells), which indicates the presence of antibodies.
Duration
The entire procedure, including blood sample collection and testing, typically takes 30 minutes to an hour.
Setting
This test is usually performed in a hospital laboratory or an outpatient clinic.
Personnel
- Phlebotomist (for blood collection)
- Laboratory technician or clinical pathologist (for test processing and analysis)
Risks and Complications
- Common risks: minor discomfort or bruising at the blood draw site
- Rare risks: infection at the puncture site, lightheadedness or fainting during blood draw
Benefits
- Identification of harmful antibodies, which can prevent complications in blood transfusions and pregnancy.
- Early detection and management of hemolytic disorders.
- Enhanced safety in organ transplantation.
Recovery
There are no significant recovery steps for the patient, as the test is non-invasive. Patients can resume normal activities immediately after the blood draw.
Alternatives
- Direct Coombs Test: Used to detect antibodies attached to the patient’s red blood cells rather than in the serum.
- Enzyme-linked Immunosorbent Assay (ELISA): Another method to detect specific antibodies, though not specifically for red blood cell antibodies.
- Flow Cytometry: Can be used for more detailed immunological analysis.
Pros and cons of alternatives depend on the specific diagnostic requirements and the patient's condition.
Patient Experience
- During the Procedure: The patient may feel a small prick or mild discomfort during the blood draw. Some might experience lightheadedness.
- After the Procedure: Slight bruising or tenderness at the site of blood draw, which typically resolves quickly. Comfort measures include pressing on the site with a cotton ball and keeping it clean. Pain management is usually unnecessary but can involve over-the-counter pain relievers if discomfort persists.