What are the causes of elevated serum amylase (Amylase) levels?

From the Guidelines

Elevated amylase levels in the blood can be caused by several conditions, with pancreatic disorders being the most common, and it is crucial to consider the clinical context and measure lipase simultaneously to differentiate between acute and chronic conditions. Acute pancreatitis is the primary cause, where inflammation of the pancreas leads to release of amylase into the bloodstream, often resulting in levels 3-5 times the normal range 1. Other pancreatic causes include pancreatic cancer, pancreatic duct obstruction, and pancreatic pseudocysts. Non-pancreatic causes include salivary gland disorders like mumps or salivary stones, kidney dysfunction (as amylase is cleared by the kidneys), intestinal disorders such as bowel obstruction or perforation, and certain medications like opiates, diuretics, and oral contraceptives. Macroamylasemia, a benign condition where amylase binds to proteins preventing kidney clearance, can also cause elevated levels without disease. Trauma to amylase-producing organs, diabetic ketoacidosis, and certain tumors may also increase amylase levels. Some key points to consider when evaluating elevated amylase levels include:

• The degree and duration of elevation can help differentiate between acute and chronic conditions 1
• Lipase elevation is more specific for pancreatic disorders than amylase, with a sensitivity and specificity of 79% and 89%, respectively 1
• Other biomarkers such as intestinal fatty acid-binding protein (I-FABP), serum alpha-glutathione S-transferase (alpha-GST), and cobalt-albumin binding assay (CABA) may be useful in the diagnosis of acute mesenteric ischemia, but their accuracy and values require further research 2, 3
• Elevated amylase has been reported in roughly half of patients with acute mesenteric ischemia, which can lead to misdiagnosis as having acute pancreatitis 3 It is essential to note that no single test shows optimal diagnostic accuracy, and most current guidelines and recommendations indicate that lipase should be preferred over total and p-amylase for the diagnosis of acute pancreatitis 1.

From the Research

Causes of Elevated Amylase

• Elevated amylase levels can be caused by various conditions, including pancreatic and non-pancreatic diseases 4
• Non-pancreatic conditions that may cause elevated amylase levels include intra-abdominal inflammatory conditions, such as salivary gland dysfunction 5
• Salivary gland involvement has been observed in patients with chronic pancreatitis, particularly those with autoimmune and idiopathic etiologies 5
• Other causes of elevated amylase levels may include acute pancreatitis, although amylase levels are not specific for this condition and can be elevated in other diseases as well 4, 6
• The diagnosis of acute pancreatitis is often based on clinical symptoms and laboratory testing, including serum amylase and lipase levels, although lipase is considered a more sensitive and specific marker 6
• Elevated amylase levels can also be seen in patients with other conditions, such as those with abdominal pain, and may not always be indicative of pancreatitis 4, 7

Diagnostic Considerations

• Serum amylase and lipase levels are not sufficient to diagnose acute pancreatitis, and radiological evidence and clinical evaluation are also necessary 4, 8
• The use of lipase alone may be sufficient for the diagnosis of acute pancreatitis, as it offers a higher sensitivity and a larger diagnostic window than amylase 6
• However, both lipase and amylase lack the ability to determine the severity and etiology of acute pancreatitis, and other diagnostic tools, such as scoring systems and imaging studies, may be necessary 6, 7