1. A classification system for the antigens of human blood; used in blood transfusion therapy; four groups are A and B and AB and O
   - ABO blood group system, ABO system

Type of: classification system

• blood sugar
• blood test
• blood transfusion
• blood type
• blood typing
• blood vessel
• blood-and-guts
• blood-brain barrier
• blood-filled
• blood-oxygenation level dependent functional magnetic resonance imaging
• blood-red
• blood-related
• blood-twig
• bloodbath
• catechin
• catechise
• catechism
• catechismal
• catechist
• catechistic
• catechize
• catecholamine
• catechu
• catechumen
• categorem