  It is shown that the lesser and greater self energies and Green functions
calculated in a recent work on universal noequilibrium transport in interacting
quantum dots [E. Mu\~noz, C. J. Bolech, and S. Kirchner, Phys. Rev. Lett. 110,
016601 (2013)] are incorrect. The authors start from renormalized second-order
perturbation theory in the Coulomb repulsion in the particle-hole symmetric
impurity Anderson model. The reported lesser self-energy is compared with the
correct one, and with an analytic result valid for small frequency and applied
voltage. As a consequence of the mistakes, the conservation of the current is
not established and the results are unreliable.
