Which blood transfusion is correct ?

Options

A. A` to `B
B. B `to` A
C. AB `to `A
D. O `to` A

Answer

To determine which blood transfusion is correct, we need to analyze the compatibility of different blood types based on the ABO blood group system. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Blood Types and Antigens
- Blood types are classified based on the presence of specific antigens on the surface of red blood cells (RBCs).
- **Blood Group A** has antigen A and antibodies against B.
- **Blood Group B** has antigen B and antibodies against A.
- **Blood Group AB** has both antigens A and B, and no antibodies against A or B.
- **Blood Group O** has no antigens and has both antibodies against A and B.

### Step 2: Identify Universal Donor and Recipient
- **Universal Recipient**: Blood group AB can receive blood from any group (A, B, AB, or O) because it has no antibodies against A or B.
- **Universal Donor**: Blood group O can donate to any group because it has no antigens that would trigger an immune response.

### Step 3: Analyze the Given Options
- **Option A (A to B)**: Incorrect. A cannot receive blood from B because A has antibodies against B.
- **Option B (B to A)**: Incorrect. B cannot donate to A because B has antibodies against A.
- **Option C (AB to A)**: Correct. AB can donate to A since A will not have an immune reaction against AB.
- **Option D (O to A)**: Incorrect. O has antibodies against A, so it cannot donate to A.

### Conclusion
The only correct transfusion option is **AB to A**.