Reducing sugar in urine can be detected by –
**Core Concept**
Reducing sugar in urine is a characteristic feature of diabetes mellitus, particularly the uncontrolled hyperglycemia that results in glycosuria. Glucose is not reabsorbed in the kidneys when blood glucose levels exceed a certain threshold, leading to its excretion in the urine. This phenomenon is a classic sign of diabetes mellitus.
**Why the Correct Answer is Right**
The correct answer is based on the principle of glucose reabsorption in the proximal convoluted tubule of the kidneys. Normally, glucose is reabsorbed into the bloodstream through a sodium-glucose cotransporter (SGLT2) in the renal tubules. However, when blood glucose levels exceed 180-200 mg/dL, the capacity for glucose reabsorption is exceeded, leading to its appearance in the urine. This is a crucial diagnostic feature of diabetes mellitus.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because reducing sugar in urine is not a characteristic feature of diabetes insipidus, which is a separate condition involving the regulation of water in the body.
* **Option B:** This option is incorrect because reducing sugar in urine is not a direct result of liver disease, although liver disease can lead to secondary complications that may result in glycosuria.
* **Option C:** This option is incorrect because reducing sugar in urine is not a characteristic feature of hypoglycemia, which is a condition of low blood glucose levels.
**Clinical Pearl / High-Yield Fact**
Reducing sugar in urine is a classic sign of uncontrolled diabetes mellitus, particularly in the absence of other symptoms. Healthcare providers should always investigate glycosuria further to rule out other causes and to initiate timely management of the underlying condition.
**Correct Answer: A. Benedict's test**