Lipase Test: Purpose, Procedure, and Results
Though many people may not realize it, the pancreas plays an important role in our digestive process. It can, therefore, be a serious concern when diseases of the pancreas cause it to stop functioning properly. Indeed, acute pancreatitis, a disease characterized by inflammation of the pancreas, is the most prevalent cause of hospitalization for those with gastrointestinal disorders in the United States. Each year, nearly 275,000 Americans are hospitalized with acute pancreatitis, and the condition (as well as other pancreatic disorders) is often diagnosed with a tool called a serum lipase test.
What Does the Pancreas Do?
Located behind the stomach, the pancreas is somewhat unusual in that it is part of both the digestive system and the endocrine system. In its function within the endocrine system, the pancreas is primarily responsible for regulating blood sugar levels and metabolism through the production of insulin. As part of the digestive system, the pancreas secretes pancreatic “juice” that is used in digestion.
When food enters the body, the first part of digestion is actually a combination of chewing and enzymes released by the salivary gland. After this masticated food makes its way down the esophagus and into the stomach, it is broken down by digestive juices secreted by the stomach. This food bolus then enters the small intestine where it is subjected to, among other substances, pancreatic juices. These juices are a mix of enzymes that break down food into components that are usable by the body. One of the main enzymes in this mixture is lipase (another is amylase).
What is Lipase?
Enzymes work on a molecular level to break down larger molecules into smaller ones that can be absorbed by the body and used in cellular function. Lipase is one such enzyme that is responsible for breaking down dietary fats, which in biology are known as lipids. When human pancreatic lipase (HPL) encounters lipids, it causes a chemical reaction that leads to hydrolysis; this is a process whereby water molecules actually rupture the chemical bonds of lipids.
One example of lipase in action is with triglycerides. A triglyceride is a type of lipid that is composed of a molecule of glycerol and three fatty acids. The body can’t use triglycerides as-is, so they require lipase to act as a catalyst. The lipase enzyme causes the triglyceride to come apart, leaving the glycerol and fatty acids free to be absorbed by the body and eventually become used as energy.
What Is a Lipase Test?
In addition to serving its digestive function, the presence of lipase in greater than normal amounts can also be an indicator of a problem with the gastrointestinal system. When the pancreas and the digestive system are functioning normally, anywhere from 0 to 160 units per liter of lipase can be detected in the bloodstream. When elevated, however, that amount can soar to many times higher than the normal levels. A lipase test is used to determine the amount of lipase in the blood and potentially rule in or out a variety of medical conditions.
Hyperlipasemia, the technical term for high blood lipase levels, is often associated with disrupted pancreatic function. When this happens, for any number of reasons, the pancreas can begin to produce too much lipase; the production of too much lipase can, in turn, cause autolysis, the destruction of cells because of the body’s own enzymes. Though the suspicion of acute pancreatitis is one of the main reasons a lipase test might be performed, high lipase levels may also indicate a variety of conditions:
- Pancreatitis: inflammation of the pancreas
- Pancreatic tumors: though possible with pancreatic cancer, elevated lipase levels are typically observed in non-cancerous pancreatic tumors
- Gallbladder infection: inflammation of the gallbladder (cholecystitis), often caused by gallstones, can cause the bile ducts to be blocked and force pancreatic juices (including lipase) back into the pancreas
- Kidney disease or kidney failure: some of the pancreatic enzymes are actually produced in the kidneys, so elevated levels may also indicate kidney problems
- Bowel obstruction: in some cases where the small intestines are blocked, pancreatic enzymes may build up
- Celiac disease: though not well understood, there appears to be a connection between patients with celiac disease and an increased risk of pancreatitis
- Duodenal ulcer: these somewhat common ulcers occur in the part of the small intestine where pancreatic juices enter
- Cystic fibrosis: high lipase levels can be a diagnostic marker
Symptoms Associated with Hyperlipasemia
A gastroenterologist won’t typically suspect pancreatitis or any condition associated with elevated lipase levels without the patient first experiencing symptoms. Though elevated lipase levels won’t necessarily cause symptoms, those that do present may be similar to or in addition to symptoms that accompany pancreatitis or even diabetes:
- Excessive thirst
- Frequent urination
- Extreme fatigue or weakness
- Weight loss
- Pain in the middle of the chest
- Back pain
- Abdominal pain
Risk Factors for Pancreatitis
As one of the main causes of high lipase levels, the risk factors for pancreatitis are highly relevant. This is especially true in terms of the function of lipase in metabolizing triglycerides. Not surprisingly, then, people with high blood triglyceride levels and who are obese are more likely to develop pancreatitis. Other risk factors include excessive alcohol consumption, gallstones, and a history of pancreatitis.
How Is a Lipase Test Administered?
The (mostly) good news for patients is that the lipase test can be done by a simple blood test: drawing a blood sample and testing it in a lab. The healthcare provider will require you to not eat anything in the eight hours leading up to the test, and he or she may also advise you to refrain from taking any medications that could potentially influence test results; some examples of these medications are birth control pills, thiazide diuretics, indomethacin, or opioids like morphine and codeine.
Blood tests, like many laboratory tests, can be anxiety-producing for many people, but the actual risk of any blood test is extremely low. For the vast majority of people, there are no side effects or risks at all. Some patients will experience bruising at the site where the needle entered the skin as well as potentially a feeling of lightheadedness; bleeding and infection are also potential but rare outcomes.
What Happens if I Have Pancreatitis?
As noted earlier, the lipase test is most often used to diagnose pancreatitis, an inflammation of the pancreas. This condition is typically caused by either gallstones or excessive alcohol consumption, though other causes are possible. It is certainly a serious condition, but it is also very treatable; most treatments include pain medication, intravenous fluids, and occasionally antibiotics. In cases where gallstones are the cause, removal of the gallbladder may be necessary.
Ultimately, a lipase test is a relatively simple affair that can help doctors pinpoint the cause of elevated lipase levels and potentially uncover a pancreatic disease. If you have been experiencing any of the symptoms of acute or chronic pancreatitis and would like to speak with a gastroenterologist, contact us at Cary Gastroenterology Associates; our board-certified physicians are dedicated to providing high quality, compassionate health care.