How often should serum iron and ferritin be monitored with PN supplementation after starting a repletion dose?

How often should serum iron and ferritin be monitored with PN supplementation after starting a repletion dose?

• A. Weekly
• B. Every 1 to 3 months
• C. Every 6 months
• D. Never

Answer: (B)

The key idea is to track iron status at intervals that reflect gradual replenishment without overtesting. When you start a repletion dose in parenteral nutrition, iron stores should rise slowly, so checking how much iron is stored over time helps you gauge response and avoid overload. Ferritin is the best stored-iron indicator, but it can be affected by inflammation, so you interpret ferritin trends rather than a single value. Serum iron can vary day to day, so using both measurements over time gives a clearer picture of true iron status. Checking these labs every 1 to 3 months provides a practical balance between detecting under-repletion or excess and not burdening the patient with excessive testing. Weekly monitoring is unnecessarily frequent once repletion has begun, every 6 months could miss important changes, and never would ignore potential safety concerns.

The key idea is to track iron status at intervals that reflect gradual replenishment without overtesting. When you start a repletion dose in parenteral nutrition, iron stores should rise slowly, so checking how much iron is stored over time helps you gauge response and avoid overload. Ferritin is the best stored-iron indicator, but it can be affected by inflammation, so you interpret ferritin trends rather than a single value. Serum iron can vary day to day, so using both measurements over time gives a clearer picture of true iron status. Checking these labs every 1 to 3 months provides a practical balance between detecting under-repletion or excess and not burdening the patient with excessive testing. Weekly monitoring is unnecessarily frequent once repletion has begun, every 6 months could miss important changes, and never would ignore potential safety concerns.