Introduction: A debated question in gastroparesis (GP) is whether the severity of isotope retention determines the variance in symptoms. Hence, our aim was to assess if the severity of symptoms induced by a standard radiolabeled eggbeater meal could distinguish the categories of food retention in GP. Methods: Patients with symptoms suggesting an upper GI motility disorder underwent a scintigraphic gastric emptying (GE) test. GP patients were categorized as mild, moderate, severe and very severe based on percent isotope retention at 4 hrs: 10-20%, 20-35%, 35-50% and >50%, respectively. Symptoms of nausea, fullness, bloating and abdominal pain were graded from 0-4 (none, minimum, mild, moderate and severe) by questioning the patient prior to, immediately after the meal, and hourly over the 4 hrs. Adjusted association between GP severity and symptoms were assessed using repeated logistic regression analysis. Results: 103 GP patients were recruited, average age of 50 [range: 18 - 86] and 75% females. The gastric retention in the majority of the patients was mild (36%) and very severe patient (33%), followed by moderate (23%) and severe (8%). Of the 103 GP patients, 42% had diabetes (DM) with the very severe gastric retention group having the highest percentage of DM (45%). After adjusting for diabetes, moderate retention patients were more likely to experience more nausea and bloating symptoms (Figures 1 and 2) (OR: 2.03, p=0.108; OR: 2.27, p=0.08), while very severe were less likely to experience bloating and abdominal pain (OR: 0.47, p=0.09; OR: 2.43, p=0.06) when compared to the mild gastric retention group. Moreover, DM patients had a statistical increase in the likelihood of experiencing nausea over nondiabetics (OR: 1.17, p=0.104; OR: 1.98, p=0.04). Fullness increased postprandially with no significant differences observed among the groups<./p>420_A Figure 1. Nausea in GP patients across the 4-hr meal420_B Figure 2. Bloating in GP patients across the 4-hr mealConclusion: We conclude that after a standard GE test meal: 1) nausea and bloating best correlate with a moderate gastric retention severity status (20-35%) and postprandial fullness is increased in all retention categories; 2) DM patients had greater nausea sensitivity; 3) There is disparity between very severe gastric retention (>50%) and decreased symptom severity, particularly with abdominal pain. Explanations include a chronically distended antrum being unable discriminate postprandial symptoms, the eggbeater test meal is insufficient in volume to provoke symptoms, and both DM and non-DM etiologies impair gastric neurosensory function.