Upon initiation of home parenteral nutrition (HPN), laboratory data should be obtained within:

• A. 24 hours
• B. 48 hours
• C. 72 hours
• D. 96 hours

Answer: (B)

Initiation of home PN requires prompt laboratory monitoring to catch early metabolic changes and guide safe adjustments to the regimen. Getting labs within 48 hours provides a baseline and an early signal for issues such as electrolyte disturbances (potassium, phosphate, magnesium), glucose abnormalities, triglyceride elevation, and any changes in renal or liver function as the body responds to the new nutrition. Detecting these problems within the first couple of days allows timely modifications to the PN formulation, electrolyte supplementation, and fluid or insulin/insulin management if needed, reducing the risk of complications like refeeding syndrome. Waiting longer than 48 hours can delay necessary corrections, while drawing strictly at 24 hours may miss evolving disturbances.