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Urine melanin
Definition
Urine melanin is a test to determine the abnormal presence of melanin in the urine.
Alternative Names
Thormahlen's test; Melanin - 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 done to diagnose melanoma because there are better tests available.
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.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. 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. Health Solutions, Ebix, Inc.
