Transfusing Rh-Negative Platelets to Rh-Positive Recipients
Yes, you can safely transfuse apheresis platelets from an Rh-negative donor to an Rh-positive recipient without any special precautions or concerns. This is the reverse of the clinically relevant scenario and poses no immunologic risk.
Why This Is Safe
The concern with Rh compatibility in platelet transfusion only flows in one direction: Rh-negative recipients receiving Rh-positive platelets 1. The reverse scenario (your question) has no clinical significance because:
- Platelets themselves do not express RhD antigens on their surface 1
- An Rh-positive recipient already has RhD antigens on their own red blood cells and cannot be "sensitized" to an antigen they already possess 1
- The small amount of contaminating RBCs in platelet products (approximately 0.00043 mL in apheresis products) from an Rh-negative donor contains no RhD antigens that could cause any reaction 1
The Clinically Relevant Scenario (For Context)
The American Society of Clinical Oncology guidelines extensively address the opposite situation—giving Rh-positive platelets to Rh-negative recipients—because this can cause RhD alloimmunization 1. Even in that scenario:
- The risk of alloimmunization is only 1.44% (7 of 485 patients in the largest study) 1
- Prevention measures are recommended primarily for female children and women of childbearing potential being treated with curative intent 1
- These measures need not be applied universally due to the low overall risk 1
Clinical Bottom Line
Proceed with the transfusion without any modifications. Rh-negative platelets to an Rh-positive recipient is the safest possible Rh mismatch scenario in platelet transfusion and requires no RhIG prophylaxis, no special monitoring, and no documentation beyond standard transfusion records 1.