Standard Protocol Variables
| Category | Variable | Definition |
|---|---|---|
| Patient preparation | Medication withholding | Prokinetic agents: metoclopramide, tegaserod (Zelnorm; Alfasigma USA, Inc.), domperidone, erythromycin, and cisapride; opiates; anticholinergic and antispasmodic agents; atropine, nifedipine, progesterone, octreotide, theophylline, benzodiazepine, and phentolamine |
| Withholding time | Two days | |
| Blood glucose | Testing of blood glucose level before study to ensure level is <200 mg/dL | |
| Blood glucose recording | Recording of blood glucose level and including it in final report | |
| Meal | Consensus meal | Proper preparation of meal with all 4 listed ingredients and no other ingredients (e.g., no butter or juice): 118 mL (4 oz) of liquid egg whites, 120 mL of water, 2 slices of toast, 30 g of jam or jelly |
| Nothing by mouth | No food or water by mouth for minimum of 4 h | |
| Meal ingestion time | Consumption of meal as quickly as possible and in less than 10 min | |
| Partial meal | Instructions in cases of vomiting or if patient ingests only a portion of meal | |
| Radiopharmaceutical dose | 18.5–37 MBq (0.5–1.0 mCi) of 99mTc sulfur colloid | |
| Acquisition | Image projections | Acquisition of both anterior and posterior images |
| Image frequency | Acquisition of images immediately on meal completion and hourly until 4 h | |
| Processing | Geometric mean | Calculation of geometric mean using anterior and posterior projections (geometric mean = √ (anterior counts × posterior counts) |
| Decay-corrected | Decay correction of counts in region of interest | |
| Percentage retention | Reporting of final measurements as percentage gastric retention at each time point |