A model of weak phase fluctuations of polycrystalline films of biological fluids is proposed. A correlation approach has been used to describe the polarization manifestations of the linear and circular birefringence of biological planar polycrystalline networks. Algorithms of polarization experimental measurement of the module (orientation map) and phase (phase map) of a set of "two-point" parameters of the Stokes vector are determined. The sets of orientation and phase maps of polycrystalline films of bile and blood are studied experimentally. The diagnostic possibilities of statistical analysis of the module and phase distributions of the "two-point" parameters of the Stokes vector of polarization-inhomogeneous images are considered. The magnitudes and ranges of changes in the set of statistical moments of the 1st and 4th orders that characterize the orientation and phase maps of polycrystalline films of bile and blood are found. The sensitivity, specificity and balanced accuracy of the method of polarization-correlation mapping in the diagnosis of early stage of cholelithiasis, as well as differentiation of the degree of blood losses, were determined.