How many hours before the anticipated operation should autologous blood not be drawn?

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

Answer: (B)

The main idea is that autologous blood donation should be separated from the time of surgery by a safe interval to keep the patient’s red cell mass adequate at the operation and to allow some recovery from the donation. Stopping autologous blood draws 72 hours before the planned surgery gives a buffer period for the body to stabilize and reduces the risk of significant anemia or hemodynamic instability during the operation. Donating within 24 or 48 hours would be too close to surgery to ensure adequate red cell rebound and patient safety, while waiting as long as 96 hours isn’t typically necessary. So the recommended cutoff is 72 hours before the procedure.