👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Safety & Infection Control🔖 Free to read, print, and share
Also known as: blood types · transfusion compatibility · ABO Rh · blood matching
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Use this quick-reference guide to spot, treat, and prevent ABO Blood Compatibility on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
✅ Donor
O- = universal donor
AB+ = universal recipient
📌 Rules
A gets A or O
B gets B or O
Rh- gives to + or -
✅ Do
TWO RN verify at bedside
Y-tubing w/ NS only
Stay first 15 min, slow rate
✅ Reaction
STOP transfusion immediately
Fever, chills, flank pain, ↓BP
Keep IV open w/ NS
📚 ABO Blood Compatibility — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
ABO and Rh typing determines which blood a patient can safely receive, since transfusing incompatible blood triggers a deadly hemolytic reaction. Type O negative is the universal red cell donor, and type AB positive is the universal recipient. Correct patient and blood verification is one of the highest-priority safety checks in nursing.
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Key points
Understand these first
Type O negative red cells are the universal donor and are used in emergencies before typing.
Type AB positive is the universal recipient because the plasma has no A or B antibodies.
Rh-negative patients should receive Rh-negative blood to prevent sensitization.
Mismatched ABO blood causes an acute hemolytic transfusion reaction that can be fatal.
Two qualified staff must verify the patient and blood product identity at the bedside.
Blood is administered through a filtered set and only with normal saline.
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Nursing priorities
What to do, in order
Verify patient identity, blood type, and unit number with a second nurse before starting.
Stay with the patient and monitor vital signs closely during the first 15 minutes.
Start the transfusion slowly and watch for early signs of a reaction.
Stop the transfusion immediately at the first sign of a reaction and keep the IV open with saline.
Use only normal saline with blood and never mix medications into the line.
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Red flags — report now
Escalate immediately
Fever, chills, flank or back pain, dark urine, or hypotension during transfusion signal a hemolytic reaction; stop it at once.
Never hang blood that does not exactly match the verified patient and order.
Never infuse blood with any solution other than normal saline.
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Labs & values
Numbers to know
Type and crossmatch required before transfusion
ABO groups: A, B, AB, O
Rh factor: positive or negative
O negative = universal RBC donor
AB positive = universal recipient
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Patient teaching
What patients must know
Report any chills, itching, back pain, shortness of breath, or feeling unwell during a transfusion right away.
Understand the reason for transfusion and that staff will check vital signs frequently for safety.
❓ ABO Blood Compatibility: NCLEX FAQs
What are the priority nursing interventions for ABO Blood Compatibility?
Verify patient identity, blood type, and unit number with a second nurse before starting. Stay with the patient and monitor vital signs closely during the first 15 minutes. Start the transfusion slowly and watch for early signs of a reaction. Stop the transfusion immediately at the first sign of a reaction and keep the IV open with saline.
What are the warning signs of ABO Blood Compatibility a nurse must report?
Fever, chills, flank or back pain, dark urine, or hypotension during transfusion signal a hemolytic reaction; stop it at once. Never hang blood that does not exactly match the verified patient and order. Never infuse blood with any solution other than normal saline.
What do I need to know about ABO Blood Compatibility for the NCLEX?
Type O negative red cells are the universal donor and are used in emergencies before typing. Type AB positive is the universal recipient because the plasma has no A or B antibodies. Rh-negative patients should receive Rh-negative blood to prevent sensitization. Mismatched ABO blood causes an acute hemolytic transfusion reaction that can be fatal.
What patient teaching is important for ABO Blood Compatibility?
Report any chills, itching, back pain, shortness of breath, or feeling unwell during a transfusion right away. Understand the reason for transfusion and that staff will check vital signs frequently for safety.
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Quick Tip
Type O negative red cells are the universal donor and are used in emergencies before typing.