counting vs blood count

counting and blood count both are nouns.

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

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

counting: 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 counting include census, nose count, nosecount, countdown, miscount, poll, recount, sperm count.

counting (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
	the number of red and white corpuscles in a blood sample