Definition
The Rhesus (Rh) system classifies blood by the presence or absence of the Rh (D) antigen on the surface of RBC’s. In this test, a patient’s RBCs are mixed with serum containing anti-Rh (D) antibodies and are observed for clumping. If clumping occurs, the Rh (D) antigen is present, and the patient’s blood is typed Rh positive; if clumping doesn’t occur, the antigen is absent, and the patient’s blood is typed Rh-negative.
Purpose
- To establish blood type according to the Rh system.
- To help determine the donor’s compatibility before transfusion.
- To determine if the patient will require an Rh (D) immune globulin injection.
Procedure
Patient Preparation
- Confirm the patient’s identity using two patient identifiers according to facility policy.
- Explain to the patient that Rh typing determines or verifies blood group to ensure safe blood transfusions.
- Inform the patient that he doesn’t need to restrict food and fluids for the test.
- Tell the patient that the test requires a blood sample. Explain that he may experience slight discomfort from the tourniquet and needle puncture.
- Check the patient’s history for recent administration of dextran, IV contrast media, or drugs that may alter test results.
Implementation
- Perform a venipuncture and collect the sample in a 7-mL EDTA tube.
- Label the sample with the patient’s name, the hospital or blood bank number, the date, and your initial.
- If a transfusion is ordered, make sure a transfusion request form accompanies the sample to the laboratory.
Nursing Interventions
- Apply direct pressure to the veniouncture site until bleeding stops.
- If a hematoma develops at the venipuncture site, apply direct pressure.
- If necessary, give the pregnant patient a card identifying that she may need to receive Rh (D) injection.
Interpretation
Normal Results
- If the D antigen is present, that person is Rh positive.
- If the D antigen is absent, that person is Rh-negative.
- Antibodies to Rh antigens develop only as an immune response after a transfusion or during pregnancy.
Abnormal Results
- Rh incompatibility is the most common and severe cause of HDN, possible when Rh-negative woman and an Rh-positive man produce an Rh positive baby.
Interfering Factors
- Unknown
Precautions
- Handle the sample gently and send it to the laboratory immediately.