Urine melanin

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

How the Test is Performed

A clean-catch urine sample is needed.

How to Prepare for the Test

No special preparation is needed.

How the Test Will Feel

The test involves only normal urination.

Why the Test is Performed

This test is used to diagnose melanoma, a type of skin cancer that produces melanin. If the cancer spreads (especially within the liver), the cancer may produce enough of this substance that it shows up in the urine.

Normal Results

Normally, melanin is not present in urine.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

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

Risks

There are no risks associated with this test.

Considerations

This test is rarely performed as there are better diagnostic tests available.

Alternative Names

Thormahlen's test; Melanin - urine

References

McPherson RA, Ben-Ezra J, Zhao S. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 27.

Updated: 4/24/2012

Reviewed by: Linda Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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