Polyglucose dialysis solution (PG-DS) decreases serum amylase activity owing to interference in the analytical method. The interference can make it difficult to diagnose pancreatitis. Our aim was to check whether, during PG-DS administration, serum lipase activity changes simultaneously with serum amylase activity, and, if so, what the reason is for the detected change. Studies were started in 14 continuous ambulatory peritoneal dialysis (CAPD) patients in whom 7.5% PG-DS was applied for the overnight exchange. In addition to standard clinical and laboratory data, serum activity of lipase and of total amylase were evaluated at 1.6 +/- 0.8 months before PG-DS introduction (period I, n = 14), after 1.2 +/- 0.6 months of PG-DS administration (period II, n = 14), after 4.4 +/- 0.8 months of PG-DS administration (period III, n = 11), after 8.8 +/- 2.2 months of PG-DS administration (period IV, n = 9), and at 2.0 +/- 0.6 months after PG-DS discontinuation (period V, n = 11). The PG-DS was also added to serum from CAPD patients with known activity of amylase and of lipase. Immediately and 3 hours after PG-DS addition, a significant decrease in total amylase activity was seen; lipase activity was unchanged. In consecutive study periods, the results (median and range) were: for lipase activity--50 U/L (12-131 U/L), 59 U/L (25-160 U/L; p < 0.05 vs period I), 73 U/L (26-158 U/L; p < 0.05 vs period I), 66 U/L (30-203 U/L; p < 0.05 vs period I), and 44 U/L (15-112 U/L); for amylase activity--81 U/L (43-249 U/L), 14 U/L (5-82 U/L; p < 0.05 vs period I and period V), 15 U/L (5-192 U/L; p < 0.05 vs period I), 15 U/L (10-93 U/L; p < 0.05 vs period I and period V), and 118 U/L (4-221 U/L). An increase in serum lipase activity over the normal range (27-65 U/L) was not accompanied by clinical symptoms of pancreatic dysfunction, but rises were simultaneously shown in blood urea nitrogen, in serum level of creatinine and of total calcium, and in calcium phosphorus product. Our results confirm PG-DS influence on amylase determinations, exclude PG-DS interference in lipase measurements, and indicate that long-term PG-DS administration influences pancreatic exocrine function at a subclinical level.