What does urine specific gravity reflect?

• A. The presence of bacteria
• B. The concentration of solutes in urine
• C. The color of urine
• D. The volume of urine produced

Answer: (B)

Urine specific gravity reflects how concentrated the urine is, i.e., the amount of dissolved solutes per volume. It measures density relative to water, so more solutes (electrolytes, urea, uric acid, and other metabolites) raise the value, while fewer solutes lower it. A high value means concentrated urine (often due to dehydration or increased water reabsorption by the kidneys); a low value means dilute urine (from high fluid intake or impaired concentrating ability). It does not measure bacteria, urine color, or the total volume produced, though changes in hydration and kidney function can influence SG.