  The derivation of the quasiclassical Lorentz invariant neutrino spin
evolution equation taking into account general types of neutrino non-derivative
interactions with external fields is presented. We discuss the constraints on
the characteristics of matter and neutrino under which this quasiclassical
approach is valid. The application of the obtained equation for the case of the
Standard Model neutrino interactions with moving and polarized background
matter is considered.
