131I Rose Bengal scanning and clearance ratios in the investigation of jaundiced patients.

It may be difficult to distinguish between obstructive and non-obstructive jaundice despite the use of clinical, biochemical and radiographic tests. Endoscopic cannulation tests promise to be the most accurate means of separating the two groups, but they are not yet widely available, and are not entirely safe. In contrast, the 131I-Rose Bengal test is simple, safe and comparatively widely available. Its accuracy in 70 jaundiced patients is reviewed to determine whether it still has a place in the investigation of jaundiced patients. Blood clearance traces, intestinal radioactivity traces and serial abdominal scans were done during a period of 3 h. The blood clearance ratios were not helpful discriminators, and the most helpful information was the timing of intestinal radioactivity. Its rapid appearance excluded mechanical obstruction. A delay of up to 3 h in its appearance was characteristic of cholestasis. A delay of more than 3 h was found in all cases of mechanical obstruction, but also in ten cases of severe cholestasis which could not be distinguished from those with mechanical obstruction. A follow-up examination within another ten days was of diagnostic value in two of these cases and the overall accuracy of the test was 86%. The potential value of prolonging the test to 24 h is discussed. It is concluded that the 131I-Rose Bengal test is a helpful diagnostic discriminator in the great majority of patients with jaundice. It is offered as a screening procedure for specialised techniques.