The shortcomings of existing drug discovery for protease inhibitors give rise to products such as nelfinavir, a putative HIV protease inhibitor. Nelfinavir is now known to induce acute pancreatitis and this work demonstrates that it promotes digestion of serum proteins, especially serum albumin, by digestive proteases. A diagnostic for acute pancreatitis demonstrates the presence of digestive enzymes in the serum. Taken together, it is postulated that the unspecified “catabolism” driver for hypoalbuminemia is proteolysis. The relative benefits of ESR_SL for drug screening and potential use in the clinic are shown.