Urine melanin

Alternative names:

melanin - urine; Thormahlen's test

How the test is performed:

Child or adult:
Collect a "clean-catch" ("midstream") urine sample. To obtain a clean-catch sample, men or boys should wipe 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 (this clears the urethra of contaminants). Then, in a clean container, catch about 1 to 2 ounces of urine and remove the container from the urine stream. Give the container to the health care provider or assistant.

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 your 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. Place a diaper over the infant (bag and all). Check your baby frequently and remove the bag after the infant has urinated into it. For active infants, this procedure may take a couple of attempts--lively infants can displace the bag, causing an inability to obtain the specimen. The urine is drained into a container for transport back to the health care provider.

How to prepare for the test:

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

How the test will feel:

The test involves only normal urination.

Why the test is performed:

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, melanin will be present in the urine, where it normally is not.

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