What is an amylase blood test?
Amylase is a digestive enzyme that helps the body break down carbohydrates. Both the salivary glands and the pancreas produce amylase. Several different medical conditions can affect amylase levels in the blood.
Doctors can also use a urine test to check a person's amylase levels.
In this article, we explore the conditions that doctors might diagnose using amylase blood tests and explain how to prepare for the test and what to expect. We also cover what the normal amylase range is and what high and low levels can mean.
When is it used?
An amylase test requires a blood sample.
A variety of medical conditions can affect amylase levels in the blood.
The primary producers of amylase in the body are the pancreas and the salivary glands in the mouth. Approximately 40 percent of the amylase in the blood comes from the pancreas, which means that amylase blood tests can help diagnose conditions that affect the pancreas.
Doctors use amylase blood tests to diagnose or monitor the following conditions:
Doctors commonly use amylase blood tests to diagnose or monitor people with acute pancreatitis.
Pancreatitis is inflammation of the pancreas. Pancreatitis can be acute, meaning that a person has the condition for a short period, or chronic, which means that the inflammation is longer-term or recurring.
Pancreatitis can cause severe abdominal pain and swelling. Other symptoms can include:
- nausea or vomiting
- upset stomach
- jaundice, which is a yellowing of the skin and the whites of the eyes
To help diagnose pancreatitis, a doctor may order an amylase blood test. Abnormally high or low levels of amylase in the blood can be a sign that a person has pancreatitis.
Other tests for pancreatitis may include:
- Imagining tests, such as a CT scan, MRI scan, or ultrasound. These tests create images of the inside of the body, allowing a doctor to look for signs of inflammation and determine its severity.
- Lipase blood tests. The pancreas also produces a digestive enzyme called lipase. Abnormal levels of lipase can also be a sign of pancreatitis.
According to the American Cancer Society (ACS), there is an association between chronic pancreatitis and an increased risk of developing pancreatic cancer, particularly in people who smoke. However, the ACS also state that most individuals with pancreatitis do not get pancreatic cancer.
Amylase and lipase tests are useful in diagnosing or monitoring tumors and cancers that affect the pancreas.
Some case studies suggest a potential link between higher-than-normal levels of amylase, particularly in the saliva, and ovarian tumors.
Two case studies suggest that there may be an association between high amylase levels in the blood and lung cancer. Therefore, checking a person's amylase levels may help doctors diagnose and monitor lung cancer.
Some medication may affect amylase levels.
Other conditions and factors that can affect amylase levels in the blood may include:
- gallbladder attacks
- pancreatic cysts or sores
- gastrointestinal or digestive problems
- kidney problems
- having had a recent kidney transplant
- mumps, which is an infection of the salivary glands
- diabetic ketoacidosis
- eating disorders
- some medications
How to prepare
It is not usually necessary to fast or make any specific preparations before having an amylase blood test.
However, some medications can increase amylase levels, which can make the test results difficult to interpret. A doctor may recommend temporarily stopping certain medicines before the test, so it is essential to inform them of any current medications or supplements.
People should also avoid consuming alcohol before the test.
What to expect?
The amylase blood test is a routine blood test. A healthcare professional will clean a small area of the person's skin and then insert a needle to draw a sample of blood. This procedure usually only takes a few minutes. They will then send the sample to a laboratory for analysis.
What is the normal range?
Normal amylase levels vary from person to person and according to the testing methods of the lab. However, many labs consider a person's amylase levels to be healthy if they are between 19 units per liter (U/L) and 86 U/L.
A doctor may recommend further tests to diagnose a condition accurately.
High amylase levels are typically a sign of acute or chronic pancreatitis. Acute pancreatitis can cause amylase levels to become four to six times higher than the upper limit of the normal range.
Other conditions may cause amylase levels to increase, including:
- pancreatic cancer
- ovarian cancer
- lung cancer
- cholecystitis and other conditions that can affect the gallbladder
- mumps and other conditions that can affect the salivary glands
- diabetic ketoacidosis
- ectopic pregnancy
- blockages in the pancreas, bile duct, or intestines
- peptic ulcers
- salivary gland tumors, for example, in the parotid gland
Chronic pancreatitis can damage the pancreas over time, which can eventually lead to a decrease in the amount of amylase in the blood.
Low amylase levels in the blood may also be a sign of:
Amylase is a digestive enzyme that the pancreas and salivary glands produce. Doctors typically use amylase blood tests to help diagnose and monitor people with acute or chronic pancreatitis. However, abnormal amylase levels can also be a sign of many other conditions.
An amylase blood test is a routine blood test that generally requires no specific preparation. As some medications can interfere with the results, a doctor may advise temporarily stopping these before the test.