Key learning points:

• The standard protocol for gastric emptying is critical for standardization across different institutions and different points of time.
• The most sensitive time point for diagnosing delayed gastric emptying is the 4 hour time point (>10% retention).
• Delayed gastric emptying grades include
  • Grade 1 (mild): 11-20% retention
  • Grade 2 (moderate): 21-35% retention
  • Grade 3 (severe): 36-50% retention
  • Grade 4 (very severe): >50% retention
• Delayed gastric emptying is commonly found in diabetics, post-surgery, post-viral infection, and idiopathically.