What is being tested?Trypsinogen is a proenzyme, an inactive precursor to the proteolytic enzyme trypsin. Normally, trypsinogen is produced in the pancreas and transported to the small intestine. In the small intestine, it is activated, turned into trypsin by an
enzyme in the intestinal mucosa, forming a powerful chemical responsible for breaking down the
protein in food into smaller pieces called peptides.
In people with
cystic fibrosis, mucous plugs can block the pancreatic ducts that lead into the small intestine, preventing trypsinogen from reaching the intestine and preventing the breakdown of food proteins. Infants are screened using a test called
immunoreactive trypsin (IRT). Those newborns with CF may have elevated levels of IRT in their blood for several months, whereas in normal infants, any temporary
false- positive elevations in trypsinogen will usually fall to normal low levels within a few weeks.
In other diseases, such as chronic
pancreatitis and
pancreatic cancer, pancreas tissue damage may cause blockages that prevent trypsinogen from reaching the small intestine. The cells that produce trypsinogen can also become damaged or be destroyed, decreasing the body's supply. Both blockages and cell damage can cause
pancreatic insufficiency.
