Persons with 'AB' blood group are called as "Universal recipients". This is due to :

The correct answer is: Absence of antibodies, anti‑A and anti‑B, in plasma.

To understand why individuals with blood type AB are called “universal recipients,” we need to review the basics of the ABO blood‑group system.

1. Red blood‑cell (RBC) antigens
- Blood type A cells have antigen A on their surface.
- Blood type B cells have antigen B on their surface.
- Blood type AB cells have **both** antigens A **and** B on their surface.
- Blood type O cells have **no** A or B antigens.

2. Plasma antibodies
- The plasma of a person contains antibodies that target antigens **not** present on their own RBCs.
- Type A plasma contains anti‑B antibodies.
- Type B plasma contains anti‑A antibodies.
- Type O plasma contains both anti‑A and anti‑B antibodies.
- **Type AB plasma contains **none** of these antibodies**; it lacks anti‑A and anti‑B.

3. Transfusion compatibility
- When transfusing blood, the donor RBC antigens must not be attacked by the recipient’s plasma antibodies.
- If the recipient’s plasma contains anti‑A or anti‑B antibodies, receiving blood with the corresponding antigen would cause an agglutination reaction.

4. Why AB individuals can receive any blood type
- Since AB plasma lacks both anti‑A and anti‑B antibodies, there are **no** antibodies to react against A or B antigens on donor RBCs.
- Therefore, an AB recipient can safely receive red cells from type A, type B, type AB, or type O donors.

In summary, the universal‑recipient property of the AB blood group stems from the **absence of anti‑A and anti‑B antibodies in their plasma**, which prevents any immune reaction against incoming A or B antigens.