Yes, PRETRIAL is a Scrabble word!

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

Is it a valid word?

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

(law) a conference held before the trial begins to bring the parties together to outline discovery proceedings and to define the issues to be tried; more useful in civil than in criminal cases

Also: pretrial conference.