immunoassay vs bio-assay

immunoassay and bio-assay both are nouns.

Word	Noun	Adjective	Verb	Adverb
immunoassay	Yes	No	No	No
bio-assay	Yes	No	No	No

As nouns, bio-assay is a hypernym of immunoassay; that is, bio-assay is a word with a broader meaning than immunoassay:

immunoassay: identification of a substance (especially a protein) by its action as an antigen
bio-assay: appraisal of the biological activity of a substance by testing its effect on an organism and comparing the result with some agreed standard

Other hypernyms of immunoassay include bioassay.

immunoassay (noun)	bio-assay (noun)
identification of a substance (especially a protein) by its action as an antigen	appraisal of the biological activity of a substance by testing its effect on an organism and comparing the result with some agreed standard