Sensitivity, Specificity, and Predictive Values of Abnormal Emptying at 1 and 2 Hours Compared with 4 Hours

Gastric retentionSensitivitySpecificityPositive predictive valueNegative predictive value
>90% at 1 h31% (14/45)97% (123/127)78% (14/18)80% (123/154)
>60% at 2 h59% (26/44)94% (122/130)76% (26/34)87% (122/140)
  • The standard for a 4-h abnormal value was a retention of greater than 10% (Tougas et al. (1)). The data in parentheses were used for the calculation. The numerator is the number of patients correctly assigned by the intermediate time criterion to the same category as the 4-h criterion (e.g., abnormal emptying), and the denominator is the total number of patients from that category evaluated at the given time. One true-positive was not evaluated at 2 h, and 3 true-negatives were not evaluated at 1 h; hence, only 44 of the 45 patients with abnormal emptying at 4 h were evaluated at 2 h, and only 127 of 130 patients with normal emptying at 4 h were evaluated at 3 h.