DefinitionUrine specific gravity is a laboratory test that measures the concentration of all chemical particles in the urine.See also:Urine concentration testUrine osmolalityUrinalysisAlternative NamesUrine densityHow the test is performedThe test requires a clean-catch urine sample. For information on how to collect this urine sample, see: Clean-catch urine cultureHow to prepare for the testYour health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test. Drugs that can increase specific gravity measurements include dextran and sucrose. Receiving intravenous dye (contrast medium) for an x-ray exam up to 3 days before the test can also interfere with results.Eat a normal, balanced diet for several days before the test.How the test will feelTh