Indocyanine green clearance as a test for hepatic function. Evaluation by dichromatic ear densitometry.

Abstract

A study of clearance of dyes which are removed from the circulation principally by the liver constitutes one of the best methods for evaluating hepatic function. This approach has not been widely used because of the need for multiple blood sampling to calculate accurately removal rate of sulf obromophthalein (BSP) and for radioisotope-counting equipment for clearance studies of rose bengal I 131.¹These disadvantages are largely overcome by indocyanine green (ICG), which possesses physical properties which permit external recording of blood dye levels. The major limitation of ICG has been the fact that, in doses conventionally used, it has proven much less sensitive than BSP in detecting mild liver-cell damage²or demonstrating the excretory defect produced by synthetic androgenicanabolic steroids.³ Levels of ICG have been recorded by use of an air-cooled oximeter to measure light transmission⁴or electric eye to determine light reflection.⁵Accuracy of