Urine specific gravity test
Urine specific gravity is a laboratory test that measures the concentration of all chemical particles in the urine.
How the test is performed
After you provide a urine sample, it is tested right away. The health care provider uses a dipstick made with a color-sensitive pad. The color the dipstick changes to will tell the provider the specific gravity of your urine. The dipstick test gives only a rough result. For a more accurate result, your health care provider may send your urine sample to a lab.
How to prepare for the test
Your health care provider will ask you to temporarily stop any medicines that may affect the test results. These may include dextran and sucrose. Be sure to tell your provider about all the medicines you take. Do not stop taking any medicine before talking to your provider.
Also tell your provider if you recently received intravenous dye (contrast medium) for an x-ray. The dye can also affect test results
How the test will feel
The test involves only normal urination. There is no discomfort.
Why the test is performed
This test helps evaluate your body's water balance and urine concentration.
This test helps check your body's water balance and urine concentration.
Osmolality is a more specific test for urine concentration. The specific gravity test is easier and more convenient, and is usually part of a routine urinalysis. As such, the osmolality test may not be needed.
What abnormal results mean
Increased urine specific gravity may be due to different conditions such as:
- Diarrhea that causes dehydration
- Heart failure
- Loss of body fluids (dehydration)
- Narrowing of the kidney artery (renal artery stenosis)
- Sugar, or glucose, in the urine
- Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
Decreased urine specific gravity may be due to:
- Damage to kidney tubule cells (renal tubular necrosis)
- Diabetes insipidus
- Drinking too much fluid
- Kidney failure
- Severe kidney infection (pyelonephritis)
What the risks are
There are no risks with this test.
Gerber GS, Brendler CB. Evaluation of the urologic patient: history, physical examination, and urinalysis. In: Wein AJ, Kavoussi LR, Novick AC, et al., eds. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 3.
McPherson RA, Ben-Ezra J. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 28.