The amylase blood test measures the concentration of the digestive enzyme amylase circulating in the bloodstream. Amylase is a protein that plays an important part in the body’s digestive process. Measuring this enzyme helps diagnose various medical conditions. Elevated levels often suggest a medical problem, most frequently involving the pancreas, which is one of the main organs responsible for producing the enzyme.
The Role of Amylase in the Body
Amylase is an enzyme that acts as a biological catalyst, helping the body break down complex carbohydrates into simpler sugars like maltose and glucose. This process, known as hydrolysis, is the first step in carbohydrate digestion and allows the body to absorb these sugars for energy. The production of amylase is largely centered in two locations: the pancreas and the salivary glands in the mouth.
The salivary glands produce amylase that begins starch digestion immediately upon chewing food. The pancreas is the source of the majority of amylase, secreting it into the small intestine to complete the breakdown of starches. Normally, only a small amount of this enzyme circulates in the blood. Significantly higher amounts indicate the enzyme has leaked out of its normal pathway, usually due to damage or inflammation in the producing organs.
Why Doctors Order the Test
Doctors most frequently order an amylase blood test to help diagnose or monitor conditions affecting the pancreas, particularly acute pancreatitis. The test is useful when a patient presents with symptoms such as severe abdominal pain that may radiate to the back, nausea, vomiting, or fever.
The test also assists in monitoring chronic pancreatitis, a long-term inflammation that can progressively damage the organ. The amylase test may also be ordered if a doctor suspects a blockage in the pancreatic duct, often caused by gallstones, which impedes enzyme flow. Less common reasons for ordering the test include:
- Investigating symptoms related to salivary gland disorders, such as mumps.
- Diagnosing other causes of abdominal pain like a perforated ulcer or intestinal obstruction.
Understanding the Test Procedure and Preparation
The amylase blood test is a standard laboratory procedure involving a simple venipuncture to draw a small blood sample from the arm. The entire collection process is quick, typically taking only a few minutes. The sample is then sent to a laboratory for analysis of the amylase concentration.
Preparation for the test requires patients to follow their doctor’s specific instructions. Fasting is not always required, but some doctors may ask for it or advise against consuming alcohol for 24 hours before the blood draw. Disclosure of all prescription and over-the-counter medications is important because several drugs, including certain diuretics, opioids, and oral contraceptives, can affect amylase levels.
Interpreting Amylase Levels
The typical reference range for amylase in the blood is 30 to 110 units per liter (U/L), though this range can vary between different laboratories. When amylase levels are significantly high, often three to six times the upper limit, it strongly suggests acute pancreatitis. This elevation occurs because the inflamed pancreas releases a surge of the enzyme into the bloodstream.
High amylase levels can also be caused by non-pancreatic conditions:
- Salivary gland infections (e.g., mumps).
- Kidney failure.
- Abdominal issues like a bowel obstruction.
Low amylase levels, while less common, can indicate advanced chronic pancreatitis, where enzyme-producing cells are permanently damaged. Low results may also be linked to severe liver disease or conditions like cystic fibrosis. A healthcare professional must interpret the amylase result in combination with clinical symptoms, medical history, and other diagnostic tests.