Simple and rapid measurement of platelet-activating factor (PAF) in whole blood.

A simple assay of platelet-activating factor (PAF) in whole blood was developed, employing acetone extraction and thin layer chromatography (TLC) purification of blood sample. The activity of acetylhydrolase present in blood sample was almost completely suppressed by ice-cold acetone extraction, and other inhibitory substances interfering the activity of PAF were effectively removed from the acetone extract by TLC. Then, the treated samples were subjected to a conventional PAF bioassay using rabbit platelets. The recovery rate of PAF by the above procedure was constant and feasible (46-48%). The lower limit of the present assay was estimated to be 1.0 x 10(-10) M. Employing the present method, it was able to determine the amount of PAF in blood (1.2-6.0 x 10(-10) M) of 6 out of 14 septic patients, while no significant PAF activity was detected in the samples from 6 healthy subjects. These results indicate a potential application of the present method in the clinical assay of PAF in blood.