lymphopenia vs blood disease

lymphopenia and blood disease both are nouns.

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

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

lymphopenia: an abnormally small number of lymphocytes in the circulating blood
blood disease: a disease or disorder of the blood

Other hypernyms of lymphopenia include blood disorder.

lymphopenia (noun)	blood disease (noun)
an abnormally small number of lymphocytes in the circulating blood	a disease or disorder of the blood