“…[61][62][63] The recognition of different classes and etiologies of liver disease, their influence on patient morbidity and mortality, and the development of medical and surgical therapies demanded the introduction of techniques not only for diagnosis but also for assessment of disease severity, as judged by the impairment of overall liver performance and ultimately its impact on prognosis. The early decades of the 20th century witnessed the development of a serum bilirubin test, 64 utilization of Bauer's 1906 galactose test, 65 hippuric acid synthesis assays 66 based on the research of Armand J. Quick (of Quick Test fame 67 ), and tests based on the disposal by the body of a rainbow of dyes: indigo carmine, Congo red, methylene blue, Evans blue, Rose Bengal, indocyanine green (ICG), and arguably the most popular, the nowobsolete bromsulphalein (BSP) that is gloriously purple in alkaline solution.…”