Test for hyperamylasemia?

From the Guidelines

To test for hyperamylasemia, serum lipase is considered a more reliable diagnostic marker than serum amylase due to its higher sensitivity and larger diagnostic window.

Diagnostic Markers

• Serum lipase: remains elevated for a longer period than serum amylase, rising within 4 to 8 h, peaking at 24 h, and decreasing to normal or near normal levels over the next 8 to 14 days 1
• Serum amylase: rises within 6 to 24 h, peaks at 48 h, and decreases to normal or near normal levels over the next 3 to 7 days 1

Diagnostic Accuracy

• Serum lipase has a sensitivity of 79% and specificity of 89% for acute pancreatitis, while serum amylase has a sensitivity of 72% and specificity of 93% 1
• A Cochrane revision found that lipase should be preferred over total and p-amylase for the diagnosis of acute pancreatitis due to its higher sensitivity and larger diagnostic window 1

Clinical Guidelines

• The 2019 WSES guidelines for the management of severe acute pancreatitis recommend using serum lipase as the preferred diagnostic marker over serum amylase 1
• The United Kingdom guidelines for the management of acute pancreatitis also recommend using serum lipase or amylase activity to diagnose acute pancreatitis, with lipase being more specific 1

From the Research

Diagnostic Tests for Hyperamylasemia

To diagnose hyperamylasemia, several biochemical tests can be used, including:

• Total serum amylase test
• Lipase test
• Pancreatic amylase test
• Isoamylase test
• Phospholipase A2 test

Test Characteristics

The characteristics of these tests are as follows:

• Total serum amylase test: nonspecific marker, can be elevated in various conditions, including pancreatic and non-pancreatic diseases 2, 3
• Lipase test: specific for the pancreas, can replace total amylase test for diagnosis of acute pancreatitis in hyperamylasemia patients 2, 3
• Pancreatic amylase test: specific for the pancreas, can replace total amylase test for diagnosis of acute pancreatitis in hyperamylasemia patients 2, 3
• Isoamylase test: satisfactory for diagnosing acute pancreatitis, can be used alone or in combination with phospholipase A2 test 4
• Phospholipase A2 test: can be used in combination with isoamylase test to increase sensitivity and specificity for diagnosis of acute pancreatitis 4

Clinical Applications

These tests can be used in various clinical scenarios, including:

• Diagnosis of acute pancreatitis in patients with hyperamylasemia 2, 3, 4
• Evaluation of patients with inflammatory bowel disease 5
• Diagnosis of macroamylasemia in patients with abnormally elevated serum amylase 6

Test Interpretation

When interpreting these tests, it is essential to consider the following:

• Reference values for each enzyme should be established 2, 3
• The diagnostic accuracy of each test should be evaluated using receiver operating characteristic (ROC) curves 2
• The best cutoff values for each test should be determined to optimize sensitivity and specificity 2, 3