There are several rare blood types, some of which are unique to specific populations. The rarest blood type is Rhnull, which occurs in fewer than 1 in 1,000 people. However, of the eight main blood types, AB- is the least common, with just 0.6% of people in the U.S. having this blood type. Other rare blood types include:

• Ro: This blood type is invaluable for patients with sickle cell disease and is often used to treat them.

• Vel negative: This blood type is more common in Caucasians and is one of the rarest blood types, occurring in only 1 in 5000 people.

• Km: This blood type is found in less than 1% of the population and is often used to treat people with sickle cell disease.

Its important to note that having a rare blood type doesnt mean that your blood is better or worse than others, its just a genetic difference. However, it does mean that people with rare blood types are extremely important donors, as their blood could be vital for a patient who shares that subtype.