After a review of first two causes of bisalbuminemia: genetic mutation and overdosage during antibiotherapy with beta-lactamines, the authors underline the importance of searching for a bisalbuminemia during the course of pancreatic disease or when confronted with a serous collection, particularly an ascite of undetermined origin. Effectively, the finding of a bisalbuminemia in these two circumstances, after having eliminated the first two etiologies, permits the confirmation of the diagnostic of a pancreatic fistula. This diagnostic should imply exploratory surgery, even without other confirmation, and a per-op. wirsungography if the fistula is not visible macroscopically. The surgical correction of the fistula cures the patient and the bisalbuminemia disappears in several hours.