serum vs blood serum

serum and blood serum both are nouns.

Word	Noun	Adjective	Verb	Adverb
serum	Yes	No	No	No
blood serum	Yes	No	No	No

As nouns, serum and blood serum are synonyms defined as:

serum and blood serum: an amber, watery fluid, rich in proteins, that separates out when blood coagulates

serum (noun)	blood serum (noun)
an amber, watery fluid, rich in proteins, that separates out when blood coagulates	an amber, watery fluid, rich in proteins, that separates out when blood coagulates