Optimized serum pancreolauryl test for differentiating patients with and without chronic pancreatitis

The serum pancreolauryl test has limited sensitivity for detecting mild pancreatic insufficiency. The aim of this study was to optimize the serum pancreolauryl test so as to increase the probability of positive results in patients with chronic pancreatitis. The study had three parts. First, the sampling time was optimized by analyzing retrospectively the frequency of fluorescein peaks at different times from 0 to 240 min in 560 consecutive patients. Second, the calculation of serum fluorescein concentrations by means of a standard calibration factor was prospectively compared in 271 consecutive patients with a modification involving a specimen-specific calibration factor for each patient. Third, the clinical utility of the intravenous injection of secretin before ingestion of the test meal was prospectively evaluated in a further 32 patients. As a result, the optimized serum pancreolauryl test developed differs from the former version of the test in utilizing intravenous administration of secretin before the test meal, calculation of serum fluorescein based on specimen-specific calibration factors, and blood samples taken only at 0 (basal), 120, 150, 180, and 240 min. This optimized pancreolauryl test was abnormal more frequently in patients with chronic pancreatitis than was the formerly used test, especially for cases of mild and moderate disease.

Glucose Interference in the Pancreolauryl Test

The influence of the glucose concentration in urines being assayed as part of a pancreolauryl test was investigated. Paired patient urines ( n = 5) were assayed at 60° and 70°C, before and after spiking to 5% glucose. The influence of assay temperature alone was assessed using glucose-free paired patient urines ( n = 10). Aqueous glucose solutions and spiked (5% glucose) normal random urines ( n = 5) were assayed to assess the effect of glucose concentration alone. There was no difference in T/K ratios for glucose-free patient samples at 60°, 70° and 80°C. After spiking with glucose T/K ratios were significantly different when assayed at 70°C, but not when assayed at 60°C. Aqueous glucose solutions ≥ 0.6% produced a pigment at temperatures ≥ 65°C which absorbed at the λmax of fluorescein. Glucose was found to interfere in the pancreolauryl test. Caution should be exercised when interpreting results from glucosuric samples.