Method for home monitoring of urinary amylase after pancreas transplantation

Urinary amylase activity (UAA) is used for diagnosis of rejection in bladder-drained pancreas grafts. Unfortunately, most rejection episodes occur after the patient has been discharged. In those cases, an early diagnosis is often difficult, and a method for home UAA monitoring is needed. We have developed a method that can be used for this purpose. The method, based on Kodak dry-film technology, is shown to have good response to the wide range of UAA seen in these patients compared with responses to standard laboratory kinetic methods. The analysis (performed by the patient) involves 1) collecting urine for 24 h in a 4-L container, 2) diluting the urine with tap water to a total urine of 4 L, and 3) placing a drop of this dilution onto a slide. The slide is read by a handheld spectrophotometer that displays the UAA in secreted units per hour. The reliability of this system has been tested for wide changes of urine pH, volume of the drop applied to the slide, and tap water from different sources. Temperature coefficients have been determined to correct changes in ambient temperatures. The final handheld prototype is being developed based on these preliminary studies. This device could be of benefit for the early diagnosis of rejection episodes in recipients of bladder-drained pancreas grafts after hospital discharge.