How useful is paracetamol absorption as a marker of gastric emptying? A systematic literature study.

Functional dyspepsia is a common disorder in primary care and gastroenterology units; however, the pathophysiology is poorly understood. Delayed gastric emptying is present in nearly 40% of patients. We evaluated the validity of the paracetamol absorption test in comparison with scintigraphy for gastric emptying assessment. Studies comparing scintigraphy with paracetamol absorption were selected through a structured Medline search. A correlation coefficient between scintigraphy and paracetamol absorption over 0.6 was considered good, between 0.45 and 0.6 intermediate, and below 0.45 poor. Feasibility was assessed by studying the administration of paracetamol, frequency of blood sampling, duration of the test period, and parameters used in the analysis. Thirteen studies were identified, eight (127 subjects) found a good correlation between scintigraphy and paracetamol absorption, two studies (28 subjects) found a moderate correlation, and three (25 subjects) found no correlation. Parameters used were area under the curve (N = 9), fixed-time concentrations (N = 6), concentration-max (N = 4) and time-to-concentration-max (N = 5). Repetitive blood samples ranged from 6 to 20 samples. The durations were 1.5-8 h. In conclusion, the paracetamol absorption technique generally correlates well to scintigraphy of liquid phase gastric emptying. The execution and outcome parameters however need further standardization to optimize its' value for clinical use and research purposes.