Blood Groups & Compatibility - Mix 'n' Match Mayhem
- ABO (Landsteiner's): Natural Abs to absent A/B Ags.
- O: Anti-A/B. A: Anti-B. B: Anti-A. AB: None.
- 📌 Univ. Donor: O Rh(D)-neg. Univ. Recipient: AB Rh(D)-pos.
- ABO Compatibility:
Recipient Donor O Donor A Donor B Donor AB O ✅ ❌ ❌ ❌ A ✅ ✅ ❌ ❌ B ✅ ❌ ✅ ❌ AB ✅ ✅ ✅ ✅
- Rh System: D Ag key. Rh(D)-neg gets Rh(D)-neg blood.
- Weak D: Donor D+; Recipient D- (if sensitized).
- Rh Prophylaxis: Anti-D Ig (300 µg) for Rh(D)-neg mother/Rh(D)+ fetus.
- Bombay (Oh): No H Ag. Anti-A, -B, -H. Needs Oh blood.
- Testing: Typing (ABO/Rh), Screen (Abs), Crossmatch.
⭐ Bombay (Oh) lacks H Ag; only Oh blood compatible due to anti-H.
Blood Components - The Life-Saving Lineup
| Component | Key Contents | Storage (Temp, Life) | Vol. | Dose / Increment | Key Indications |
|---|---|---|---|---|---|
| PRBCs | RBCs, minimal plasma | 2-6°C, 35-42d | ~300mL | 1U ↑Hb 1g/dL or Hct 3% | Anemia (Hb<7g/dL), acute loss >20% |
| Platelets | Platelets, plasma | 20-24°C (agitate), 5d | 50-200mL | RDP: ↑5-10k/µL; SDP: ↑30-50k/µL | Thrombocytopenia (<10k/µL), active bleeding |
| FFP | All clotting factors, albumin | ≤-18°C, 1yr (Thawed: 24h, 1-6°C) | ~225mL | 10-15mL/kg; ↑factors 20-30% | Coagulopathy (INR>1.7), TTP, MTP |
| Cryo | Fibrinogen, F.VIII, vWF, F.XIII 📌 | ≤-18°C, 1yr (Thawed: 4-6h, 20-24°C) | ~15mL/U | 1U/10kg ↑Fibrinogen ~50mg/dL | Hypofibrinogenemia (<100mg/dL), vWD, F.XIII def. |
| Granulocytes | Neutrophils, some RBCs/PLTs | 20-24°C, 24h (no agitate) | ~250mL | Variable; clinical response | Severe neutropenia (<500/µL) + sepsis (unresponsive, rare) |
Transfusion Reactions - When Good Blood Goes Bad
STOP TRANSFUSION! Maintain IV. Notify blood bank.
Acute Reactions (<24h)
| Reaction | Onset | Features/Patho | Mgmt |
|---|---|---|---|
| AHTR | Mins-Hrs | ABO mismatch; Hemolysis, fever, shock | Supportive |
| FNHTR | <4h | Cytokines/WBC Abs; Temp ↑ ≥1°C | Antipyretics |
| Allergic/Anaphylactic | Mins-Hrs | IgE (urticaria); Anti-IgA (anaphylaxis) | Antihistamines/Epi |
| TRALI | <6h | Donor Abs; Non-cardiac pulm. edema, hypoxemia | O2, supportive |
| TACO | <6h | Volume overload; Cardiac pulm. edema, ↑BNP | Diuretics, O2 |
| Bacterial Contam. | Mins-Hrs | Toxins; High fever, shock | IV Abx |
Delayed Reactions (>24h)
- DHTR (3-30d): Extravascular hemolysis (IgG); ↓Hb, jaundice. Supportive.
- PTP (5-12d): Anti-platelet Abs (HPA-1a); Severe thrombocytopenia. IVIG.
- TA-GVHD (1-6w): Donor T-cells attack host; Rash, pancytopenia. Irradiate to prevent.
Special Transfusions & Safety - Handle With Care
- Massive Transfusion Protocol (MTP):
- Definition: Replacement of >1 blood volume in 24 hrs, >50% in 4 hrs, or >4 units in 1 hr.
- Ratio: 1:1:1 (PRBC:FFP:Platelets).
- Complications (📌 ACHE): Acidosis, Coagulopathy, Hypothermia, Electrolyte imbalance ($↑K^+$, $↓Ca^{2+}$).
- Transfusion Transmitted Infections (TTIs):
- Mandatory Indian screening: HIV, HBV, HCV, Syphilis, Malaria.
- Window period risk remains.
⭐ HBV is the most common TTI in India despite screening.
- Leucoreduction: Reduces febrile non-hemolytic reactions, CMV transmission. Indicated in immunocompromised, chronically transfused patients.
- Irradiation: Prevents Transfusion-Associated Graft-Versus-Host Disease (TA-GVHD). Indicated for immunocompromised, directed donations from relatives, and intrauterine/neonatal transfusions.
High‑Yield Points - ⚡ Biggest Takeaways
- O RhD negative is the universal RBC donor; AB RhD positive is the universal RBC recipient.
- AB group is the universal plasma donor; O group is the universal plasma recipient.
- FNHTR (Febrile Non-Hemolytic Transfusion Reaction) is the most common reaction, caused by cytokines from donor leukocytes.
- TACO (Transfusion-Associated Circulatory Overload) presents with fluid overload; manage with diuretics and slow infusion.
- TRALI (Transfusion-Related Acute Lung Injury) causes non-cardiogenic pulmonary edema due to donor antibodies.
- Massive transfusion protocol often uses a 1:1:1 ratio of PRBCs:FFP:Platelets.
- Irradiation of blood products prevents TA-GVHD in immunocompromised patients and directed donations from relatives.
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