Methods of preparing liquid exchanged biological fractions are provided. Aspects of the present disclosure according to certain embodiments include introducing a biological sample into a centrifugation container having a buoy, subjecting the biological sample to a force of centrifugation to produce two or more fractions in the biological sample, collecting a first fraction of the biological sample from the container and introducing a liquid exchange fluid into the container to produce a liquid exchanged fraction that is a mixture of the liquid exchange fluid and a second fraction of the biological sample. Compositions having a liquid exchanged platelet-rich fluid and kits for practicing embodiments of the subject methods are also provided. Methods for applying compositions having a liquid exchanged platelet-rich fluid to a body site of the subject are described.
