Blood Types
Your blood type is determined by antigens on the surface of your red blood cells — and getting a transfusion with the wrong type can be fatal. Understanding the ABO and Rh systems, how blood types are inherited, and which types are compatible is essential knowledge for patients, parents, and anyone curious about their biology.
Blood Type Compatibility Chart: Red Cells, Whole Blood & Plasma
Complete blood type compatibility chart for red cell, whole blood, and plasma transfusions. Covers universal donor/recipient rules, ABO matching, and pregnancy considerations.
- ✓ Compatibility rules differ for red blood cells, whole blood, and plasma — the charts are not identical
- ✓ O negative is the emergency red blood cell donor; AB positive is the universal recipient for red cells
- ✓ AB plasma can be given to patients of any blood type — making AB donors the plasma universal donors
Blood Type Distribution by Race and Ethnicity: Global ABO Data
How blood type frequencies vary by race and ethnicity worldwide. ABO distribution data across 86+ populations, medical implications of ethnic blood type variation, and why it matters for transfusion.
- ✓ Blood type frequencies vary significantly across racial and ethnic populations worldwide
- ✓ Early European populations have low type B frequency and relatively high type A
- ✓ East Asian populations tend toward higher frequencies of both A and B compared to European populations
Blood Type Inheritance: How Parents Pass Blood Types to Children
How blood type inheritance works — parent-child combination charts, Punnett squares explained simply, Rh factor genetics, and what blood type can (and can't) tell you about paternity.
- ✓ You inherit exactly one blood type allele from each parent — the combination determines your ABO type
- ✓ The three ABO alleles are A, B, and O — A and B are dominant over O, but codominant with each other
- ✓ Two O-type parents can only produce O-type children
Blood Types Chart: A, B, AB & O Explained with Full US Distribution Data
Complete blood types chart with US population distribution, ABO compatibility, Rh factor, and genetic basis. Everything you need to know about your blood type.
- ✓ O+ is the most common blood type in the US, found in about 1 in 3 people (38.4%)
- ✓ AB- is the rarest blood type, occurring in only 1 in 167 people (0.7%)
- ✓ O- is the universal donor for red blood cells; AB+ is the universal recipient
Blood Typing Systems: ABO, Rh, and the 26 ISBT Blood Group Systems
Complete guide to blood typing systems — ABO, Rh (Rhesus), MNSs, Kell, Duffy, Kidd, Lewis, and all 26 ISBT-recognized blood group systems with antigens explained.
- ✓ The ABO system, discovered in 1901, remains the most important blood group classification
- ✓ The ISBT recognizes 26 distinct blood group systems with hundreds of antigens between them
- ✓ The Rh system is the second most clinically important — only those with genotype cde/cde are truly Rh negative
Rare Blood Types: What Makes Blood Rare, Who Has It, and Why It Matters
What makes a blood type rare, which ethnic groups carry rare types, how rare blood registries work, and what to do if you have a rare blood type. Includes rarity charts.
- ✓ A blood type is considered rare when more than 200 donors must be screened to find one compatible match
- ✓ Approximately 1 in 1,000 people inherit a rare blood type
- ✓ Rare blood types are classified by ABO type plus over 600 additional antigens — many combinations are exceedingly uncommon