family vs blood line

family and blood line both are nouns.

Word	Noun	Adjective	Verb	Adverb
family	Yes	No	No	No
blood line	Yes	No	No	No

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

family (noun)	blood line (noun)
primary social group; parents and children	the hereditary derivation of an individual
people descended from a common ancestor
a social unit living together
(biology) a taxonomic group containing one or more genera
a collection of things sharing a common attribute
an association of people who share common beliefs or activities
a loose affiliation of gangsters in charge of organized criminal activities
a person having kinship with another or others