Value of serum PABA as a pancreatic function test.

In a total of 71 subjects (19 controls, 24 patients with non-pancreatic gastrointestinal disease, and 27 patients with pancreatic disease) an oral pancreatic function test using N-benzoyl-L-tyrosyl-PABA (BT-PABA) was performed with simultaneous determination of the serum para-aminobenzoic acid (PABA). Urinary excretion of PABA was significantly less (p less than 0.001) in patients with chronic pancreatitis (n = 12) and pancreatic carcinoma (n = 10) than in controls and in patients with non-pancreatic disease. The serum concentration curve in patients with chronic pancreatitis was significantly flattened (p less than 0.001) compared with that of the control group and the patients with non-pancreatic gastrointestinal disease. The discrimination between the controls and the patients with chronic pancreatitis was best at 120 minutes after administration of BT-PABA (lower limit of normal: 2.8 micrograms/ml). The results of our study show that determination of PABA serum concentration two hours after administration of BT-PABA is as valuable an index of pancreatic function as the urinary excretion of PABA.