blood group vs blood type

blood group and blood type both are nouns.

Word	Noun	Adjective	Verb	Adverb
blood group	Yes	No	No	No
blood type	Yes	No	No	No

As nouns, blood group and blood type are synonyms defined as:

blood group and blood type: human blood cells (usually just the red blood cells) that have the same antigens

blood group (noun)	blood type (noun)
human blood cells (usually just the red blood cells) that have the same antigens	human blood cells (usually just the red blood cells) that have the same antigens