Leucine aminopeptidase is a protein, called an enzyme, that is normally found in liver cells. This article discusses the test to measure how much of this protein appears in your urine.

Your blood can also be checked for this protein. See also: Leucine aminopeptidase - blood

A 24-hour urine sample is needed.

• On day 1, urinate into the toilet when you get up in the morning.
• Afterwards, collect all urine in a special container for the next 24 hours.
• On day 2, urinate into the container when you get up in the morning.
• Cap the container. Keep it in the refrigerator or a cool place during the collection period.

Label the container with your name, the date, the time of completion, and return it as instructed.

For an infant, thoroughly wash the area where urine exits the body.

• Open a urine collection bag (a plastic bag with an adhesive paper on one end).
• For males, place the entire penis in the bag and attach the adhesive to the skin.
• For females, place the bag over the labia.
• Diaper as usual over the secured bag.

This procedure may take a couple of attempts -- lively infants can move the bag, causing the urine to be absorbed by the diaper. Check the infant frequently and change the bag after the infant has urinated into it. Drain the urine from the bag into the container provided by your health care provider.

Deliver it to the laboratory or your health care provider as soon as possible upon completion.

Your health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test.

Your health care provider may tell you to stop taking any drugs that could affect the test. Drugs that can affect the results of this test include estrogen and progesterone. Never stop taking any medicine without first talking to your doctor.

The test involves only normal urination, and there is no discomfort.

Your doctor may order this test to see if your liver is damaged. It may also be done to check for certain tumors.

Normal values range from 2 - 18 units per 24 hours.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Increased levels of leucine aminopeptidase can be seen in several conditions:

• Cholestasis
• Cirrhosis
• Hepatitis
• Liver cancer
• Liver ischemia (reduced blood flow to the liver)
• Liver necrosis (death of live tissue)
• Liver tumor
• Pregnancy (late stage)

There is essentially no risk.

Berk P, Korenblatt K. Approach to the patient with jaundice or abnormal liver test results. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 150.