A patient complains of excessive thirst and urination. The healthcare provider wants to determine whether the condition is diabetes mellitus or diabetes insipidus. Which laboratory result would most strongly indicate diabetes mellitus?

• A. Low urine osmolarity with absent glucose in urine.
• B. Normal fasting blood glucose concentration.
• C. Elevated fasting blood glucose and positive urine glucose test.
• D. Decreased antidiuretic hormone activity with high urine volume.

Answer: (C)