Final answer:
A urine specific gravity level at or below 1.010 indicates renal disease whereby the kidney cannot concentrate urine. Concentration tests with readings below 1.020 also suggest defects in kidney functionality.
Step-by-step explanation:
A specific gravity of urine at or below what level indicates renal disease whereby the kidney cannot concentrate urine? The correct answer is: b) 1.010.
The specific gravity of urine is an important parameter for assessing the concentrating and diluting ability of the kidneys. If a concentration test using pituitrine indicates that the urine specific gravity is below 1.020 after injecting 10 USP units of pituitrine subcutaneously and collecting a 24-hour urine sample, it suggests a defect in the kidneys' reabsorption of water. This kind of impairment is characteristic of renal diseases such as Diabetes insipidus and Amyloid degeneration, where the specific gravity is often below the threshold of the normal range.
However, the answer option given for identifying renal diseases where the kidney cannot concentrate urine is 1.010. Nevertheless, specific gravity values below 1.020 after a concentration test indicate some abnormality of the kidneys. Moreover, when the specific gravity of urine is consistently low, irrespective of fluid intake, it may signal a decrease in kidney function, as the kidneys are not concentrating the urine effectively.