Rhnull blood type stands as the rarest known globally. Often dubbed "golden blood," it lacks all Rh antigens on red blood cells, with fewer than 50 documented cases worldwide.

Rarest in Standard Types

Among the common eight ABO-Rh types, AB-negative prevails as scarcest, appearing in under 1% of populations like the US. This rarity complicates transfusions, demanding precise donor matches amid urgent needs.

Why Rhnull Tops the List

Rhnull emerged in medical records since 1961, first in an Indigenous Australian, defying early doubts about adult survival. Its universal plasma compatibility for rare Rh patients elevates its transfusion value, yet carriers face hemolytic anemia risks from antigen absence. Recent 2025 mentions of "Gwada-negative" as a novel 48th group hint at ongoing discoveries, though Rhnull retains supremacy with 1-in-6-million odds.

Global Distribution Snapshot

Blood Type| Approx. Rarity| Key Notes 19
---|---|---
Rhnull| <50 cases| "Golden blood"; no Rh antigens
AB-| <1%| Rarest ABO-Rh; US stats
B-| ~2%| Varies by ethnicity
AB+| ~4%| Less common positive

TL;DR: Rhnull reigns rarest overall; AB- leads everyday types. Information gathered from public forums or data available on the internet and portrayed here.