tally vs blood count

tally and blood count both are nouns.

Word	Noun	Adjective	Verb	Adverb
tally	Yes	No	Yes	No
blood count	Yes	No	No	No

As nouns, blood count is a hyponym of tally; that is, blood count is a word with a more specific, narrower meaning than tally:

tally: the act of counting; reciting numbers in ascending order
blood count: the act of estimating the number of red and white corpuscles in a blood sample

Other hyponyms of tally include census, nose count, nosecount, countdown, miscount, poll, recount, sperm count.

tally (noun)	blood count (noun)
the act of counting; reciting numbers in ascending order	the act of estimating the number of red and white corpuscles in a blood sample
a score in baseball made by a runner touching all four bases safely	the number of red and white corpuscles in a blood sample
a bill for an amount due

tally (verb)	blood count (verb)
determine the sum of
keep score, as in games
gain points in a game
be compatible, similar or consistent; coincide in their characteristics