1. ABO Blood Group System 🅰️🅱️
| Blood Type | Antigen on RBC | Antibody in Plasma | Can Donate To | Can Receive From |
|---|---|---|---|---|
| A | A | Anti-B | A, AB | A, O |
| B | B | Anti-A | B, AB | B, O |
| AB | A and B | None | AB only | ALL (Universal Recipient) |
| O | None | Anti-A, Anti-B | ALL (Universal Donor) | O only |
2. Rh Blood Group System 🔴
Rh D Antigen
- Rh Positive: D antigen present (85% of population)
- Rh Negative: D antigen absent (15% of population)
- Anti-D antibodies are acquired (IgG), not naturally occurring
Hemolytic Disease of Newborn (HDN)
- Rh- mother + Rh+ fetus = Risk of sensitization
- IgG anti-D crosses placenta, attacks fetal RBCs
- Prevention: RhoGAM (Anti-D Immunoglobulin) at 28 weeks and within 72 hrs after delivery
3. Pre-Transfusion Testing ✅
Steps in Compatibility Testing
- Patient ABO/Rh typing (forward and reverse)
- Antibody screening (Indirect Coombs)
- Crossmatch - Patient serum + Donor cells
Coombs Test (Antiglobulin Test)
- Direct (DAT): Detects antibodies on patient RBCs (autoimmune hemolytic anemia, HDN)
- Indirect (IAT): Detects antibodies in patient serum (antibody screening, crossmatch)
4. Transfusion Reactions 🚨
Acute Hemolytic (ABO Incompatibility)
- Fever, chills, back pain, hypotension
- Hemoglobinuria (red/brown urine)
- STOP transfusion immediately!
Febrile Non-Hemolytic
- Most common reaction
- Fever, chills (no hemolysis)
- Caused by WBC antibodies
Allergic
- Urticaria, itching
- Reaction to plasma proteins
- Treat with antihistamines
TRALI (Transfusion-Related Acute Lung Injury)
- Respiratory distress within 6 hours
- Pulmonary edema (non-cardiogenic)
- Leading cause of transfusion deaths
💡 Board Exam Tips - Blood Banking
- ✓ O- = Universal Donor (RBCs), AB+ = Universal Recipient
- ✓ Direct Coombs = antibodies ON cells, Indirect = antibodies IN serum
- ✓ FIRST action for any transfusion reaction: STOP THE TRANSFUSION