Lipase is an enzyme fundamental to the body’s processing of fats. The lipase blood test measures the concentration of this enzyme in the bloodstream. While a small amount of lipase is always present, measuring its level helps medical professionals assess the function of certain organs, particularly the pancreas.
The Role of Lipase in Digestion
Lipase is a digestive enzyme that breaks down dietary fats, known as triglycerides, into smaller molecules like fatty acids and glycerol. This process allows the body to absorb and utilize fats for energy and other functions. If lipase activity is inadequate, fat absorption is impaired, potentially leading to nutritional deficiencies.
The primary source of digestive lipase is the pancreas, which secretes it into the small intestine. Smaller amounts are also produced in the mouth and stomach, where initial fat digestion begins.
Why Doctors Order the Lipase Blood Test
Doctors order a lipase blood test when symptoms suggest a problem with the pancreas. When the pancreas is inflamed or damaged, the cells producing lipase are injured, causing the enzyme to leak directly into the bloodstream. Measuring this increased concentration serves as a direct indicator of pancreatic irritation.
The test is requested when a patient presents with sudden, severe upper abdominal pain that may radiate to the back, along with nausea, vomiting, or fever. Lipase is often preferred over the enzyme amylase because it is more specific to the pancreas. Furthermore, lipase levels remain elevated for a longer period, sometimes up to two weeks, aiding diagnosis even if symptoms began days earlier.
Understanding High and Low Results
Interpretation begins by comparing the measured value to the laboratory’s established reference range, which can vary between facilities. A result within this normal range indicates the pancreas is functioning without acute distress. Normal reference values are often cited as being between 0 and 160 units per liter (U/L).
Significantly elevated lipase levels are the primary clinical concern, as they are strongly linked to acute pancreatitis. A diagnosis of acute pancreatitis is supported when the serum lipase concentration is at least three times the upper limit of the normal range. This sharp increase occurs because inflamed pancreatic tissue releases a large amount of the enzyme into the circulation.
A low lipase level indicates a long-term inability of the pancreas to produce enough of the enzyme, a condition known as pancreatic insufficiency. Low levels may be seen in advanced stages of chronic pancreatitis. They can also occur in diseases like cystic fibrosis, where prolonged damage has reduced the number of functional enzyme-producing cells.
Factors That Influence Test Results
While significant elevation strongly points to acute pancreatitis, other health conditions can also cause levels to rise. Non-pancreatic issues, such as chronic kidney failure, can elevate lipase because the kidneys are responsible for clearing the enzyme from the blood. If the kidneys are not functioning properly, lipase accumulates in the bloodstream.
Other abdominal conditions, including intestinal blockage, peptic ulcers, or acute gallbladder inflammation (cholecystitis), are associated with mild to moderate lipase elevations. Certain medications can also affect the results, such as opioids and some diuretics. These drugs are known to potentially increase circulating lipase levels.
Because of these influencing factors, the lipase level alone does not provide a final diagnosis. Healthcare providers must interpret the result in conjunction with a patient’s specific symptoms and the results of other diagnostic tests, such as imaging studies or an amylase test.