Yes, PATIENT is a Scrabble word!

Letter values in Scrabble US: P 3, A 1, T 1, I 1, E 1, N 1, T 1.

Is it a valid word?

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

a person who requires medical care
the semantic role of an entity that is not the agent but is directly involved in or affected by the happening denoted by the verb in the clause

enduring trying circumstances with even temper or characterized by such endurance

Also: affected role, patient role.