Clue: Blood-type trio

Answer: ABO

Length: 3

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Similar Clues:

• Blood type historically considered the universal donor (ONEGATIVE with 9 letters)
• Blood type syst. (ABO with 3 letters)
• Rare blood type, informally (BNEG with 4 letters)
• Blood type, briefly (e.g. APOS with 4 letters)
• All of the blood-type letters (ABO with 3 letters)
• Blood trio (ABO with 3 letters)
• Common blood type, briefly (APOS with 4 letters)
• Universal donor's blood type, for short (ONEG with 4 letters)
• Blood type system (ABO with 3 letters)
• Second-commonest blood type: Abbr. (APOS with 4 letters)