Plasma paracetamol concentrations measured by fluorescence polarization immunoassay and gastric emptying time.

Radionuclide labeled gastric emptying was compared with plasma paracetamol (acetaminophen) concentration measured by fluorescence polarization immunoassay. A significant correlation was found between both gastric emptying half-time of radionuclide (t1/2) and % isotope remained in the region of the stomach and paracetamol absorption kinetic parameters. The strongest correlation was found between t1/2 and the time required to reach the peak plasma level of paracetamol (r = 0.680, p less than 0.01). This study indicates that simple paracetamol marker method has enabled an indirect quantitative measurement of gastric emptying by sampling at varying time intervals.