diagnosis vs identification

diagnosis and identification both are nouns.

Word	Noun	Adjective	Verb	Adverb
diagnosis	Yes	No	No	No
identification	Yes	No	No	No

As nouns, identification is a hypernym of diagnosis; that is, identification is a word with a broader meaning than diagnosis:

Other hypernyms of diagnosis include designation.

diagnosis (noun)	identification (noun)
identifying the nature or cause of some phenomenon	the act of designating or identifying something
	the attribution to yourself (consciously or unconsciously) of the characteristics of another person (or group of persons)
	the process of recognizing something or someone by remembering
	evidence of identity; something that identifies a person or thing
	the condition of having the identity (of a person or object) established