Abnormal circulating enzyme concentration or activity Elevated circulating pancreatic secretory trypsin inhibitor activity 2023-02-17T18:28:34Z Elevated circulating serine protease inhibitor Kazal type I Elevated circulating SPINK1 activity Increased activity of the enzyme pancreatic secretory trypsin inhibitor in the blood circulation. Pancreatic secretory trypsin inhibitor (PSTI), also known as serine protease inhibitor Kazal type I (SPINK1), binds rapidly to trypsin, inhibits its activity and is likely to protect the pancreas from prematurely activated trypsinogen. The blood concentration of PSTI may be increased in hepatocellular carcinoma and as a part of the acute phase reposnse response to infection, inflammation, tissue damage and other stressors.