• All subjects/parents must sign an informed consent and/or assent indicating that they are aware of the investigational nature of this study

• Subjects/parents must have signed an authorization for the release of their or their child's protected health information

• All children must be under 18 years of age at the time of enrollment

• All children providing samples should fit the ARP or CP inclusion criteria defined below:

‣ Acute pancreatitis (AP): AP is defined as requiring 2 of the following:

• Abdominal pain compatible with AP

∙ Serum amylase and/or lipase values \>= 3 times upper limits of normal

∙ Imaging findings of AP, such as gland enlargement, acute inflammatory changes, and fluid collections

⁃ ARP is defined as: At least 2 episodes of acute pancreatitis with complete resolution of pain and a \>= 1 month pain-free interval between episodes

⁃ Chronic Pancreatitis:

• Children with at least:

⁃ One irreversible structural change in the pancreas with or without abdominal pain +/- exocrine pancreatic insufficiency +/- diabetes

‣ Irreversible structural changes:

• Ductal calculi, dilated side branches, parenchymal calcifications found in any imaging (abdominal ultrasound \[abd US\], magnetic resonance imaging/magnetic resonance cholangiopancreatography \[MRI/MRCP\], computerized tomography \[CT\], endoscopic retrograde cholangiopancreatography \[ERCP\], endoscopic US \[EUS\])

∙ Ductal obstruction or stricture/dilatation/irregularities that are persistent (for \>= 2 months) on any imaging

∙ Parenchymal atrophy, irregular contour, accentuated lobular architecture, cavities alone are not diagnostic findings for CP

∙ Surgical or pancreatic biopsy specimen demonstrating histopathologic features compatible with CP (acinar atrophy, fibrosis, protein plugs, infiltration with lymphocytes, plasma cells, macrophages)