The most common cause of a low conductivity alarm during hemodialysis is:

• A. Air in the line
• B. Faulty dialysate temperature
• C. Improper electrolyte balance
• D. Exhausted concentrate supply

Answer: (D)

Conductivity reflects the ionic content of the dialysate. A low conductivity alarm means the dialysate isn’t carrying enough ions. In dialysis systems, dialysate is made by mixing water with electrolyte concentrates. When the concentrate supply is exhausted, there aren’t enough electrolytes in the mixture, so the dialysate becomes diluted and its conductivity drops, triggering the alarm. Replacing the concentrate and ensuring the supply is adequate typically brings conductivity back to normal.

Air in the line would more often cause flow- or air-related alarms rather than a conductivity problem. Faulty dialysate temperature affects temperature readings and alarms, not conductivity. Improper electrolyte balance could lower conductivity, but the most common real-world cause is an exhausted concentrate supply, which directly reduces the ion content of the dialysate.