From the Research
Causes of Elevated Urine Specific Gravity (USG)
The causes of elevated urine specific gravity (USG) can be attributed to various factors, including:
- Clinical conditions such as uncontrolled diabetes mellitus, nephrotic syndrome, and the administration of intravenous radiocontrast material or saline diuresis 1
- Heat exposure, as seen in heat-exposed workers, which can lead to kidney damage and elevated USG 2
- Dehydration or insufficient fluid intake, particularly in individuals who experience significant sweat losses 3
- High levels of certain substances in the urine, such as protein, glucose, ketones, bilirubin, and urobilinogen, which can affect the correlation between USG and osmolality 4
- Body composition, specifically fat-free mass, which has been shown to be positively associated with USG in athletes and active adults 5
Factors Affecting USG
Several factors can influence USG, including:
- Urine osmolality, which has a linear correlation with USG, but can be affected by various clinical conditions 1, 4
- pH levels, which can impact the correlation between USG and osmolality 4
- Presence of certain substances in the urine, such as protein, glucose, and ketones, which can affect USG measurements 4
- Body size and composition, particularly fat-free mass, which can influence USG in athletes and active adults 5
- Hydration status, which can be affected by fluid intake and sweat losses, and can impact USG measurements 3