3.11　Clinical Role of Pancreatic Function Tests

Since both morphological and functional impairment，can be the only sign of histologically proven chronic pancreatitis（Albashir et al.2010），experts agree that a pancreatic function test can be required for the diagnosis of chronic pancreatitis（HaPanEU 2016）.Proof of impaired exocrine function using function testing is particularly required for diagnosis in chronic pancreatitis patients with inconclusive morphological findings.Moreover，several diagnostic and classification systems take exocrine function into account（Layer et al.1994；Ammann 1997；Buchler et al.2009）but are usually only employed in clinical studies.

Function testing is also recommended in newly diagnosed chronic pancreatitis patients to screen for exocrine insufficiency（HaPanEU 2016），and national and international guidelines recommend repetitive testing at annual intervals in patients with previously normal results（HaPanEU 2016；Hoffneister et al.2012；Martinez et al.2013），in order to detect maldigestion prior to the occurrence of overt clinical symptoms.Apart from this，function tests should be repeated when symptoms occur or deteriorate and can be attributable to pancreatic exocrine insufficiency（HaPanEU 2016）.To evaluate the efficacy of enzyme replacement therapy，it is usually sufficient to verify clinical parameters such as the normalization of nutritional parameters and symptomatic improvement.However，when symptoms of exocrine insufficiency persist in spite of adequate pancreatic enzyme treatment indirect function tests that evaluate the effect of enzyme activity（13C-mixed triglyceride breath test，acid steatocrit，quantitative fecal fat）are recommended in order to evaluate treatment efficacy（HaPanEU 2016）.(https://www.daowen.com)

From a practical point of view，verification of pancreatic exocrine insufficiency by a pathological pancreatic function test is a prerequisite for reimbursement of enzyme treatment in some countries.