A radioimmunoassay for measurement of human pancreatic secretory trypsin inhibitor in different body fluids.

A radioimmunoassay for measurement of human pancreatic secretory trypsin inhibitor in nanogram quantities has been developed. The sensitivity of the assay now permits examination of the inhibitor content of various body fluids, wherein other methods exhibit serious short-comings. In healthy blood donors the serum level was 8.1 microgram/l. In patients with acute pancreatitis levels as high as 320 microgram/l have been measured, and patients who underwent endoscopic retrograde cholangiopancreatography showed an elevated inhibitor level in serum immediately after the examination without any clinical signs of disease, the highest registered value being 128 microgram/l. In peritoneal lavage fluid from patients with severe acute pancreatitis levels of 5-304 microgram/l have been measured. In urine the inhibitor level is about 14 microgram/l in healthy persons. The urine from one patient with proteinuria of glomerulo-tubular type contained 380 microgram/l.