This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Hyponatremia in multiple myeloma is - 
Select and explain. 
A. TRUE, B. Relative, C. Absolute, D. Pseudo
D: Pseudo
Answer: D: Pseudo 
Explanation: • Patients with multiple myeloma also have a decreased anion gap  because the M component is cationic, resulting in retention of chloride.
• This is often accompanied by hyponatremia that is felt to be artificial (Pseudohyponatremia) because each volume of serum has less water as a result of the increased protein.