Final answer:
When a patient's blood glucose level exceeds 200 mg/dL, increased urinary output, or polyuria, is most likely due to the kidneys' inability to reabsorb excessive glucose, leading to its excretion in urine.
Step-by-step explanation:
If a patient's blood glucose level exceeds 200 mg/dL, it is most likely that they will experience increased urinary output. This condition, known as polyuria, occurs because the kidney's capacity to reabsorb glucose is exceeded.
The renal threshold for glucose is 180 mg/100 mL of blood, and any glucose concentration above this value will be excreted in the urine. High blood glucose levels, or hyperglycemia, can lead to glucosuria, where glucose appears in the urine because the kidneys cannot recover all the glucose from nascent urine.
These effects are also characteristic symptoms of diabetes mellitus, where high levels of blood glucose result in frequent urination and can cause dehydration over time.