What does a low specific gravity indicate about a patient’s urine?

A low specific gravity of urine indicates that the urine is more diluted, which often suggests that the kidneys are not properly concentrating the urine. This condition is frequently associated with diabetes insipidus, a disorder characterized by an inability to concentrate urine due to a deficiency of the antidiuretic hormone (ADH) or a receptor problem.

In diabetes insipidus, the body's capacity to retain water is compromised, leading to the excretion of large volumes of dilute urine, which results in a low specific gravity. This is a key diagnostic marker for clinicians assessing a patient’s condition.

While dehydration typically results in concentrated urine with high specific gravity, kidney damage can manifest with a range of specific gravities depending on the type and extent of the damage, and urinary tract infections usually present with normal or slightly elevated specific gravity due to concentrated urine from inflammation or infection. Understanding these distinctions helps in recognizing the significance of low specific gravity in the context of diabetes insipidus.