From the Guidelines
Elevated serum lipase and amylase levels primarily indicate pancreatic inflammation or damage, with lipase being a more reliable diagnostic marker of acute pancreatitis due to its higher sensitivity and larger diagnostic window 1.
Key Points
- Lipase and amylase are digestive enzymes produced by the pancreas to break down fats and carbohydrates, respectively.
- Elevated levels of these enzymes in the bloodstream can indicate pancreatic inflammation or damage, such as in acute pancreatitis.
- Lipase is more specific to pancreatic issues, while amylase can also rise due to problems in other areas, such as the salivary glands or small intestine.
- Typically, lipase levels rise within 4-8 hours of pancreatic injury and remain elevated longer than amylase, making lipase a more sensitive marker for pancreatic conditions 1.
- Normal lipase levels are generally 0-160 U/L, while normal amylase ranges from 30-110 U/L, though reference ranges vary between laboratories.
- Levels three times the upper limit of normal strongly suggest acute pancreatitis, especially when accompanied by characteristic abdominal pain 1.
Other Conditions that May Cause Elevated Levels
- Gallstones
- Alcohol use
- Certain medications
- Kidney disease
- Intestinal obstruction
- Other conditions, such as salivary gland or ovarian problems, can also cause elevated amylase levels 1.
Diagnostic Considerations
- A Cochrane revision found that lipase has a sensitivity of 79% and specificity of 89% for diagnosing acute pancreatitis, while amylase has a sensitivity of 72% and specificity of 93% 1.
- The combination of lipase and amylase can reach a sensitivity of 85% and specificity of 100% for diagnosing pancreatic injury, especially when used in conjunction with ultrasonography 1.
From the Research
Serum Lipase and Amylase Levels
Serum lipase and amylase levels are indicators of various conditions, including pancreatic and non-pancreatic diseases. The following points highlight the significance of these levels:
- Elevated serum levels of amylase and lipase can indicate acute pancreatitis, chronic pancreatitis, gastrointestinal tract obstruction, malignancies, and other disease conditions 2.
- In acute pancreatitis, all serum pancreatic enzymes, including amylase and lipase, are abnormally high, with lipase being the most convenient to determine due to its simplicity and low cost 3.
- Serum amylase and lipase levels can be elevated in non-pancreatic conditions, leading to false diagnoses of acute pancreatitis, and are not specific for pancreatitis 4.
- The validity of serum amylase and lipase in diagnosing acute pancreatitis/acutized chronic pancreatitis is dependent on the cut-off levels, with a 2-times upper normal range being the best cut-off level for both tests 5.
- Combined serum amylase and lipase levels can be reliable indicators of pancreatic injury, with 100% specificity and 85% sensitivity, and are time-dependent, being non-diagnostic within 6 hours or less after trauma 6.
Diagnostic Implications
The diagnostic implications of serum lipase and amylase levels are:
- Elevated levels can indicate pancreatic disease, but are not sufficient for a definitive diagnosis 3, 4.
- Radiological evidence and increased cut-off levels of enzyme elevation are necessary for an accurate diagnosis of acute pancreatitis 4.
- Serum lipase levels can be elevated in many intra-abdominal inflammatory conditions, making it essential to consider other diagnostic factors 4.
- The combination of raised serum amylase or lipase can increase sensitivity and negative predictive value in diagnosing acute pancreatitis/acutized chronic pancreatitis 5.