Yes, BILIRUBINS is a Scrabble word!

Letter values in Scrabble US: B 3, I 1, L 1, I 1, R 1, U 1, B 3, I 1, N 1, S 1.

Is it a valid word?

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

an orange-yellow pigment in the bile that forms as a product of hemoglobin; excess amounts in the blood produce the yellow appearance observed in jaundice

Not playable in Scrabble US: HEMATOIDIN, HAEMATOIDIN.