Leucine aminopeptidase is a protein, called an enzyme, which is normally found in liver cells and cells of the small intestine. This article discusses the test to measure how much of this protein appears in your urine.
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 often and change the bag after the infant has urinated into it. Drain the urine from the bag into the container given to you by your health care provider.
Deliver it to the laboratory or your health care provider as soon as possible.
Your health care provider will tell you, if needed, to stop taking drugs that may interfere with the test.
How to prepare for 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.
How the test will feel
The test involves only normal urination, and there is no discomfort.
Why the test is performed
Your doctor may order this test to see if your liver is damaged. It may also be done to check for certain tumors.
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.
Pratt DS. Liver chemistry and function tests. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 73.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.