Yes, ICTERUS is a Scrabble word!

Letter values in Scrabble US: I 1, C 3, T 1, E 1, R 1, U 1, S 1.

Is it a valid word?

ICTERUS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

yellowing of the skin and the whites of the eyes caused by an accumulation of bile pigment (bilirubin) in the blood; can be a symptom of gallstones or liver infection or anemia
type genus of the Icteridae

Also: genus icterus.