Yes, FERRITIN is a Scrabble word!

Letter values in Scrabble US: F 4, E 1, R 1, R 1, I 1, T 1, I 1, N 1.

Is it a valid word?

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

a protein containing 20% iron that is found in the intestines and liver and spleen; it is one of the chief forms in which iron is stored in the body