blood serum vs serum

blood serum and serum both are nouns.

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

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

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

blood serum (noun)	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