Urine amylase (Amylasuria)

What sample is needed for Urine amylase?

1. The sample is urine.
2. Can obtain random 2 hours urine sample.
3. Amylase is unstable in acidic urine, so adjust pH to the alkaline range.
4. Store urine at 4 °C.
   1. You can also collect 24-hour samples. Discard the first sample and then collect the rest of the 24-hour samples in the container, including the last sample.
5. Also, venous blood is collected to make the serum amylase level.
6. Don’t eat or drink for at least 2 hours for blood tests.

What are the precautions for Urine amylase?

1. Urine amylase is unstable in acidic urine. Acid urine decreases amylase levels.
2. Adjust the pH to  7.0.
3. Refrigerate the urine.
4. Avoid urine contamination by stool.
5. Dexamethasone, furosemide, methanol, ethanol, thiazide, salicylates, chloride salts, and meperidine are medications that increase the result.
6. Medication that will decrease the level is citrate.

What are the Indications for urine Amylase?

1. This test tells about pancreatic dysfunction.
2. It differentiates acute pancreatitis from other:
   1. Abdominal pain.
   2. Epigastric discomfort.
   3. Nausea and vomiting.
3. It diagnoses pancreatitis in the late stages when the blood amylase is normal.
4. Raised in acute pancreatitis, cholelithiasis, and peptic ulcer.

How will you define amylase?

1. The amylase enzyme changes starch to sugar.
2. Amylase is described into two forms:
   1. α-Amylase found in humans.
   2. β-Amylase is found in plants and bacteria.

What is the action of the amylase?

1. Amylase enzymes change starch into sugars.
2. Large polysaccharide molecules are broken into smaller dextrin, maltose, and glucose units.
3. Salivary glands have the greatest concentration, and they will convert starch into sugars (Hydrolysis of starch) while food is in the mouth and esophagus.
4. Normally, a low level of amylase is found in the blood and excreted in a small amount in the urine.
5. When the pancreas and salivary glands are inflamed, more enzymes enter the blood, and more amylase is excreted in the urine.
6. In the case of pancreatitis, the amylase level in the blood is raised for a short time, while the urine level remains for several days.

What are the sites where amylase is formed?

1. Following are the sites where amylase is formed:
   1. Salivary glands. These glands have the greatest concentration.
   2. Pancreas.
   3. Liver (little or no amylase activity).
   4. Fallopian tubes.

What are the sites where Amylase activity is found?

1. Semen, testes.
2. Ovaries, fallopian tubes.
3. Striated muscles.
4. Lungs.
5. Adipose tissue.
6. Colostrum and milk.
7. The tears.

How will be the secretion of amylase?

1. Amylase from pancreatic acini goes through the pancreatic duct into the duodenum.

2. Once in the intestine, it converts carbohydrates into simple sugars.
3. Amylase activity in the serum and urine originates from pancreatic and salivary glands.

How will be the excretion of amylase?

1. An Amylase is a small unit that can pass through the glomeruli and is found in the urine.
2. Urinary amylase clearance is increased in acute pancreatitis from normal to 3 folds.
3. A value of >550 U/L has a sensitivity of 62% and 97%, specific for acute pancreatitis.
4. In damage to the salivary glands or pancreas, more enzyme in the blood is excreted in the urine.

What are the changes in pancreatitis?

1. A prolonged amylase level in urine may be raised until 5 to 7 days.
2. The short-lived peak in blood, maybe 1 to 2 days, and return to normal.
3. In acute pancreatitis, the Amylase picture is as follows:
   1. The initial rise of 2 to 12 hours.
   2. The peak level is 12 to 72 hours.
   3. The normal level reaches 3 to 4 days (short-lived peak).
   4. Urine amylase may remain elevated up to 2 weeks after the acute episode of acute pancreatitis.

Amylase/creatinine clearance ratio:

What is the principle of amylase/creatinine clearance ratio?

1. Amylase excretion in the urine depends upon renal function, so urinary amylase excretion correlates with creatinine clearance.
2. In acute pancreatitis, amylase clearance is increased compared to creatinine in the urine.
3. The amylase/creatinine clearance ratio depends upon this function of the kidneys.

What are the advantages of the amylase/creatinine clearance ratio?

1. This is done on a random urine and serum sample instead of 2 or 24 hours.
   1. One urine and one serum sample were collected.
2. The calculation of the amylase/creatine clearance ratio normally is 1% to 4%.
3. The amylase/creatinine clearance ratio becomes abnormal after 1 to 2 days of the serum amylase level, and it will remain abnormal as long as urine amylase is present.
4. The amylase/creatinine clearance ratio is more accurate than the serum amylase.

What are the disadvantages of the amylase/creatinine clearance ratio?

1. The exact degree of specificity is still not established.
2. This may be raised in some cases of diabetic ketoacidosis and burns.
3. This may be normal in mild azotemia, but in severe azotemia, it is raised.
4. Some authors believe that this has little value.
5. The amylase/creatinine clearance ratio is decreased in macroamylasia.

What are the causes of increased urine Amylase levels?

1. Acute Pancreatitis.
2. Chronic relapsing pancreatitis.
3. Penetrating peptic ulcer to the pancreas.
4. Intestinal obstruction.
5. Acute cholecystitis.
6. Parotitis (mumps) is called sialadenitis.
7. Ruptured ectopic pregnancy.
8. Pulmonary infarction.
9. Autoimmune diseases.
10. Pancreatic cyst.
11. Peritonitis.
12. Biliary tract disease.
13. Diabetic ketoacidosis.
14. Intestinal obstruction.
15. Few lung or ovarian tumors.
16. Alcoholic intoxication.
17. Diabetic ketoacidosis.
18. Acute respiratory insufficiency.

What are the causes of decreased urine Amylase?

1. Pancreatic Insufficiency.
2. Advanced chronic pancreatitis.
3. Renal failure.
4. Liver disease (severe).
5. Liver cancer.
6. Advanced cystic fibrosis.
7. Hyperglycemia.

What are the causes of the increased Amylase/creatinine clearance ratio?

1. Pancreatitis.
2. Toxemia of pregnancy.
3. Diabetic ketoacidosis.
4. Renal insufficiency.

Normal urine picture:

Questions and answers: