Bromsulfthalein (also known as bromsulphthalein, bromosulfophthalein, and BSP) is a phthalein dye used in liver function tests. Determining the rate of removal of the dye from the bloodstream gives a measure of liver function.

Binding of sulfobromophthalein (BSP) sodium and indocyanine green (ICG) by plasma alpha-1 lipoproteins 1).

1)
Baker KJ. Binding of sulfobromophthalein (BSP) sodium and indocyanine green (ICG) by plasma alpha-1 lipoproteins. Proc Soc Exp Biol Med. 1966 Aug-Sep;122(4):957-63. PubMed PMID: 5918158.