Which donor blood group should be used for a double‑volume exchange transfusion in a 2‑day‑old A‑positive neonate whose mother is AB‑positive?

Blood Selection for Double Volume Exchange Transfusion

For this 2-day-old A+ neonate born to an AB+ mother requiring exchange transfusion, use O-negative red blood cells with AB plasma (or type-specific plasma compatible with both mother and infant). 1, 2

Blood Product Selection Principles

The American Academy of Pediatrics specifies that blood for exchange transfusion must be modified whole blood (red cells and plasma) that is crossmatched against the mother and compatible with the infant. 1, 2

Red Blood Cell Component

• Use Group O red blood cells (preferably O-negative to avoid any Rh sensitization risk) 1, 2
• Group O RBCs lack A and B antigens, preventing reaction with maternal anti-A or anti-B antibodies that may be present in the infant's circulation 1
• This is critical because the AB+ mother could have passively transferred antibodies, and the neonate's own immune system is still developing 1

Plasma Component

• Use AB plasma (which lacks anti-A and anti-B antibodies) or plasma compatible with both the infant (A+) and mother (AB+) 1, 2
• AB plasma is the universal donor plasma and will not react against the infant's A antigens 1
• Alternatively, type A plasma can be used as it is compatible with the infant's blood type 1

Clinical Rationale for This Approach

The unique physiology of neonates requires special consideration: 1

• Trans-placental transfer of maternal antibodies creates different compatibility profiles than in older children or adults 1
• The neonate's immunologically naive state means maternal antibodies may still be circulating 1
• Even though mother is AB+ (universal recipient with no naturally occurring anti-A or anti-B antibodies), the standard protocol uses O RBCs to ensure maximum safety 1, 2

Critical Safety Considerations

• Blood must be immediately available before starting the procedure - this is a high-risk intervention with approximately 3 per 1000 mortality 2
• The procedure must only be performed by trained personnel in a NICU with full monitoring and resuscitation capabilities 2
• Continuous cardiorespiratory monitoring and calcium level checks are mandatory during the procedure 2

Common Pitfall to Avoid

Do not use the infant's own blood type (A+) for the red cell component in exchange transfusion, even though it matches the baby's type. The standard is O-negative RBCs to eliminate any risk of reaction with circulating maternal antibodies and to provide maximum compatibility. 1, 2