hypervolaemia vs blood disease

hypervolaemia and blood disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypervolaemia	Yes	No	No	No
blood disease	Yes	No	No	No

As nouns, blood disease is a hypernym of hypervolaemia; that is, blood disease is a word with a broader meaning than hypervolaemia:

hypervolaemia: a blood disorder consisting of an increase in the volume of circulating blood
blood disease: a disease or disorder of the blood

Other hypernyms of hypervolaemia include blood disorder.

hypervolaemia (noun)	blood disease (noun)
a blood disorder consisting of an increase in the volume of circulating blood	a disease or disorder of the blood