Amylase testing is performed to diagnose a number of diseases that elevate amylase levels. Pancreatitis, for example, is the most common reason for a high amylase level. When the pancreas is inflamed, amylase escapes from the pancreas into the blood. Within six to 48 hours after the pain begins, amylase levels in the blood start to rise. Levels will stay high for several days before gradually returning to normal.

There are other causes of increased amylase. An ulcer that erodes tissue from the stomach and goes into the pancreas will cause amylase to spill into the blood. During a mumps infection, amylase from the inflamed salivary glands increases. Amylase is also found in the liver, fallopian tubes, and small intestine; inflammation of these tissues also increases levels. Gall bladder disease, tumors of the lung or ovaries, alcohol poisoning, ruptured aortic aneurysm, and intestinal strangulation or perforation can also cause unusually high amylase levels.

TEST

Amylase testing is done on both blood and urine. The laboratory may use any of several testing methods that involve mixing the blood or urine sample with a substance with which amylase is known to react. By measuring the end-product or the reaction time, technicians can calculate the amount of amylase present in the sample. More sophisticated methods separately measure theamylase made by the pancreas and the amylase made by the salivary glands.

The Urine testing is a better long-term monitor of amylase levels. The kidneys quickly move extra amylase from the blood into the urine. Urine levels rise six to 10 hours after blood levels and stay high longer. Urine is usually collected throughout a 2- or 24-hour time period. Results are usually available the same day.

The blood amylase test is ordered, often along with a lipase test, to help diagnose and monitor acute or chronic pancreatitis (inflammation of the pancreas) and other disorders that may involve the pancreas. A urine amylase test may also be ordered. Typically, its level will mirror blood amylase concentrations, but both the rise and fall occur later. Sometimes a urine creatinine clearance may be ordered along with the urine amylase to help evaluate kidney function since decreased kidney function can result in a slower rate of amylase clearance.