Trypsin radioimmunoassay in the diagnosis of chronic pancreatitis.

Serum immunoreactive trypsin (IRT) determination has been recommended as a screening test in chronic pancreatitis. Using a commercial radioimmunoassay kit (RIA--gnost Trypsin; Behring-Werke, Marburg/Lahn, FRG) the interassay coefficient of variation was 26--44% for three different test sera. Gel filtration chromatography profiles revealed immunoreactivity in the position of 125I-trypsin and (less than 50%) in the void volume. The test was evaluated in controls (n = 90), chronic relapsing pancreatitis (CRP;n = 60) and after total pancreatectomy (n = 5). In 65% of the CRP cases decreased IRT values were found, whereas during acute attacks of CRP supranormal and normal values were found. After total pancreatectomy IRT levels were undetectable. It is concluded that the sensitivity of this IRT test is limited and that the available test system needs improvement.