The construction of portal-systemic venous shunts is widely practiced for the relief of portal hypertension with associated bleeding esophageal varices. Information regarding the postoperative patency of such a shunt is frequently of considerable value to the surgeon. The means now available for evaluating the status of such a venous anastomosis include the use of serial barium esophagograms, splenoportography (if the spleen has not been removed), and the ammonium citrate tolerance test.1 The barium esophagogram does not yield definitive information, and the latter 2 tests carry a small but definite risk to the patient. The purpose of this report is to present our experience with a test which is simple to perform and involves little or no risk or discomfort for the patient.
After oral ingestion of fructose (levulose) by the normal individual, a certain fraction is converted to glucose during passage through the intestinal mucosa,5 and the remainder