<prompt> The test used to diagnose Dubin .lohnson syndrome is-Scrum transaminasesBromsulphalein test BSPHippuratc testGamma glutamyl transferase level  <response>: A prolonged BSP dye excretion test is diagnostic of Dubin Johnson syndrome BSP is a dye which is removed from circulation by the same mechanism as bilirubin. Reference Harsh mohan page no.593 