Lifespan's A - Z Health Information Library

Urine melanin is a test to determine the abnormal presence of melanin in the urine.

Collect a "clean-catch" (midstream) urine sample. To obtain a clean-catch sample, men or boys should clean the head of the penis. Women or girls need to wash the area between the lips of the vagina with soapy water and rinse well.

As you start to urinate, allow a small amount to fall into the toilet bowl to clear the urethra of contaminants. Then, put a clean container under your urine stream and catch 1 to 2 ounces of urine. Remove the container from the urine stream. Cap and mark the container and give it to the health care provider or assistant.

For an infant:

Thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on the infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Diaper as usual over the secured bag.

This procedure may take a couple of attempts -- lively infants can displace the bag, causing the specimen to be absorbed by the diaper. The infant should be checked frequently and the bag changed after the infant has urinated into the bag. The urine is drained into the container for transport to the laboratory.

If you are collecting urine from an infant, it may be helpful to have a few spare collection bags.

The test involves only normal urination.

Malignant melanoma is a cancerous tumor of the skin cells that produce pigment. This disease is usually visible on the skin, but if the malignant cells metastasize to internal areas of the body, you may never see the cancer.

If the skin cell tumors are growing within the body (especially within the liver), melanin may be produced in sufficient quantities to be present in the urine.

This test measures the absence or presence of melanin in the urine.

Normally, melanin is not present in urine.

If melanin is present in the urine, malignant melanoma is suspected.

There are no risks associated with this test.