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Antihuman globulin test (Coombs test); indirect, each antibody titer

CPT4 code

Name of the Procedure:

Antihuman Globulin Test (Coombs Test); Indirect, Each Antibody Titer


The Antihuman Globulin Test, commonly known as the indirect Coombs test, is a blood test used to detect antibodies that are present in the bloodstream and could bind to red blood cells.


The test is used to screen for antibodies that could cause transfusion reactions or hemolytic disease of the fetus and newborn (HDFN). It aims to prevent complications from blood transfusions and to ensure the compatibility of blood types.


  • Screening for antibodies in pregnant women that might affect the fetus
  • Prior to blood transfusion to ensure compatibility and prevent reactions
  • Investigating unexplained anemia


  • No specific preparation is typically required.
  • Inform your doctor of any medications you are taking, as they may affect the test results.

Procedure Description

  1. A blood sample is drawn from the patient’s arm using a sterile needle.
  2. The blood is collected in a test tube and sent to the laboratory.
  3. In the lab, the patient's serum is mixed with a standardized panel of red blood cells.
  4. Antihuman globulin (Coombs reagent) is added to this mixture.
  5. If antibodies are present, they will cause the red blood cells to clump together (agglutinate).


The blood draw takes a few minutes. Laboratory analysis might take several hours to a couple of days, depending on the lab’s capacity.


  • Outpatient clinic
  • Hospital laboratory


  • Phlebotomist or nurse to draw the blood
  • Laboratory technician to perform the test and analyze the results

Risks and Complications

  • Minimal risk from the blood draw, such as slight pain or bruising at the puncture site.
  • Rarely, one might experience light-headedness or fainting.


  • Identifies antibodies that could cause transfusion reactions or HDFN
  • Ensures the compatibility of blood in transfusions, potentially preventing serious complications


  • No recovery time is needed. Patients can resume normal activities immediately after the blood draw.
  • Follow any specific post-draw instructions provided by the healthcare provider, such as keeping pressure on the puncture site to minimize bruising.


  • Direct Coombs Test: Checks for antibodies attached to red blood cells rather than in the bloodstream.
  • Further immunohematologic studies: May be recommended if the indirect Coombs test results are positive.

Patient Experience

  • You may feel a small prick or sting when the needle is inserted.
  • Some minor discomfort or light bruising at the blood draw site is possible.
  • Any discomfort usually subsides quickly.

Pain management and comfort are typically not needed for this simple and quick procedure.

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