Urine Specific Gravity: What Concentration Means

A urinalysis can report several independent findings from one specimen. Specific gravity addresses concentration, whereas protein, glucose and other markers answer different questions. Read the full report rather than treating specific gravity as a summary of kidney health.^{See reference 1,See reference 2}

Urine osmolality directly measures dissolved particles and is a different laboratory test. In a comparison study, specific gravity and osmolality were related but did not agree closely enough in every type of sample to use one as an exact substitute for the other.^{See reference 2}

A more concentrated sample may follow a period with less fluid intake, while a more dilute sample may follow more drinking. The same person can produce different samples at different times. The study of specific gravity and osmolality also found that glucose, protein and other abnormal constituents can affect how the measurements relate.^{See reference 2}

The interval printed by your laboratory and the method used matter. This guide does not apply a universal high or low cutoff, and it cannot decide whether an unexpected result is a normal short-term change or a medical issue.^{See reference 1,See reference 2}

Keep the collection date and time, test method if shown, laboratory interval and the other urinalysis findings together. If the result is important to a clinical question, ask whether a repeat specimen or another measurement is needed rather than comparing a dipstick with a different method as if they were identical.^{See reference 1,See reference 2,See reference 3}

Do not restrict fluids or stop medicines to chase a target value from this page. Preparation and follow-up depend on why the test was ordered and should be agreed with your care team.^{See reference 1,See reference 2}