Final answer:
The correct diagnosis based on the provided laboratory findings is hyponatremia, characterized by low sodium levels in the blood, often due to increased water dilution or sodium loss.
Step-by-step explanation:
The question is asking to diagnose a condition based on certain laboratory findings. With serum NA+ levels less than 135 mEq/L, serum osmolality at 280 mOsm/kg, and urine specific gravity below 1.010, the correct condition is hyponatremia. Hyponatremia is characterized by lower-than-normal levels of sodium in the blood, which can occur due to excess water in the body diluting the sodium, decreased intake, or increased excretion through urine, sweat, vomiting, or diarrhea. It should not be confused with hypokalemia, which is a drop in potassium levels, or hypernatremia, an increase in blood sodium levels; the 'hypo' prefix indicates a lower concentration, while 'hyper' indicates a higher concentration. Laboratory results for hyponatremia typically show serum sodium levels below the normal range of 135-145 mEq/L.