Amylase Indications : When is it ordered? / Indications
Amylase tests are ordered in the following cases:
To diagnose and monitor acute and chronic pancreatitis or other conditions of the pancreas
Urine amylase may be done to monitor kidney dysfunction
(test done along with urine creatinine). In case of kidney malfunction the clearance for both amylase and creatinine is slow
To monitor progress made in pancreatic cancer treatment
To monitor progress after gall stone removal
Symptoms of pancreatic diseases are -
Severe abdominal pain or back pain
Loss of appetite
In some cases both urine and blood amylase are tested. The blood for the test is drawn intravenously from the upper forearm. You must not eat anything before the test.
For urine amylase test, a 24- hours urine sample needs to be collected. No alcohol must be consumed starting 24 hrs prior to the test. After you wake up in the morning the first urine sample must be avoided. Consecutive urine samples must be collected in a small container and poured into a larger container. This larger container needs to be refrigerated.
Make sure this urine sample is not contaminated with pubic hair, toilet paper, stool or any other foreign object. Make sure that you drink enough water to avoid dehydration.
Physiology : Amylase
is an enzyme which is present in the human saliva. It initiates the process of digestion and plays an important role in converting dietary starch into simpler sugars.
The reason why foods that consist of complex starch, such as potato and rice, taste mildly sweet when chewed, is the action of the enzyme amylase.
Amylase (alpha amylase) is also present in pancreas
and this aids in hydrolyzing the starch in our diet into disaccharides and trisaccharides, which are eventually converted into glucose by other enzymes. Amylase is also produced by some forms of bacteria and plants.
Normal Range :
Interpretation : Normal values
|Amylase in Blood
|Adults – 60 yrs and younger
||25-125 units per liter (U/L)
|Adults - older than 60 yrs
|Amylase in urine
|2-hour urine sample
||2-34 U /day
|24-hour urine sample
||24-408 U /day
|Amylase/creatinine clearance ratio
||1%-4% or 0.01-0.04 clearance fraction
Higher than normal values indicate –
Acute /chronic pancreatitis
• Pancreatic cancer
Other abdominal disorders
Lower than normal values in the blood and urine levels in a person showing symptoms of pancreatitis indicate a permanent damage in the amylase-producing cells of the pancreas.
S-amylase and P- amylase are variants of the amylase enzyme. The former is found in the salivary glands and the latter, which is evaluated to diagnose pancreatic conditions, is found in the pancreas.
High amylase values does not necessarily mean that you have a pancreatic condition. It can also be caused by gall stones
. Both urine and blood amylase levels can be increased in a variety of conditions such as - •
Ovarian and lung cancer •
Tubal pregnancy •
Diabetic ketoacidosis •
Intestinal obstruction •
Acute appendicitis •
The amylase test, however, is not carried out to monitor any of these conditions. Certain medications too can increase amylase levels.
References : +