Acute pancreatitis is a common and potentially severe disease in feline patients. Unfortunately, feline pancreatitis has been difficult to diagnose because cats do not consistently present with the typical clinical signs suggestive of pancreatitis in dogs or humans. Furthermore, tests used in humans and dogs are not applicable to cats. A great deal of scientific effort has been applied towards trying to develop reliable methods to diagnose feline pancreatitis. One test, feline serum trypsin-like immunoreactivity, has shown some clinical usefulness, but other conditions such as renal failure and emaciation may interfere with proper diagnosis. This study proposes to evaluate two new and promising tests, serum and urine levels of trypsinogen-activation peptide (TAP). This study will document if these new tests will more reliably diagnose feline pancreatitis than previously used tests.