Clinical usefulness of the serum carboxypeptidase B activation peptide in acute pancreatitis.
BACKGROUND The pathophysiology of acute pancreatitis involves activation of the pancreatic proenzymes. Levels of the trypsinogen activation peptide in urine in acute pancreatitis has been shown to correlate with the severity of disease. However, this peptide is unstable in urine and, because of its low molecular mass, difficult to measure. Procarboxypeptidase B has a larger activation peptide which could be more suitable for analysis in serum and urine. AIMS To study the presence of the activation peptide from procarboxypeptidase B (CAPAP) in serum and urine in acute pancreatitis. PATIENTS Urine and serum samples were obtained within 48 hours of admittance from 40 patients with acute pancreatitis. Severity was classified retrospectively according to levels of C-reactive protein and clinical course. Thirty four patients with abdominal pain from other causes were studied as controls. METHODS CAPAP was purified from human pancreatic juice. Specific antibodies were obtained and a radioimmunoassay was developed. RESULTS Levels of CAPAP in serum and urine in acute pancreatitis correlate with the severity of the attack. CAPAP is very stable, and urine contains only CAPAP whereas, in serum, cross reacting procarboxypeptidase B is found together with CAPAP. CONCLUSIONS CAPAP could be a valuable tool in the diagnosis and early determination of severity in acute pancreatitis.