The rarest blood type ever identified is called Rhnull , sometimes nicknamed “golden blood,” with fewer than about 50 known cases worldwide.

Quick basics

  • Rhnull blood completely lacks all Rh antigens on red blood cells, which makes it extraordinarily rare and medically important.
  • Among the usual “eight main” types (A, B, AB, O with +/−), AB‑negative is the rarest in the general population, found in well under 1% of people.

Why Rhnull is a big deal

  • Because it has no Rh antigens, Rhnull can sometimes be used as a kind of “universal” donor blood for people with many different rare Rh variants, so each unit is considered extremely valuable.
  • People with Rhnull may face extra health challenges, and finding compatible blood for them in emergencies is very difficult, which is why their donations are coordinated very carefully.

Fun “latest news” angle

  • Beyond Rhnull, researchers are still discovering new ultra-rare blood group systems; one recent example is a system called “Gwada” , where a single known patient has a uniquely incompatible “Gwada‑negative” profile, highlighting how complex blood typing can be.

TL;DR: If someone asks “what’s the rarest blood type?” the strict answer is Rhnull (“golden blood”) , but in everyday hospital talk about the main eight types, the rarest you’ll hear about is AB‑negative.

Information gathered from public forums or data available on the internet and portrayed here.