We present a method to calculate the pion screening mass in 2+1-flavor lattice QCD to $\mathcal{O}(\mu^2_\ell),$ where $\mu_\ell$ is the isoscalar chemical potential. Our approach is based on the expression for the free theory pion screening correlator for massless quarks. We use the Taylor expansion method to calculate the screening correlator to $\mathcal{O}(\mu^4_\ell)$. We then extract the $\mathcal{O}(\mu^2_\ell)$ Taylor coefficient of the screening mass from the Taylor coefficients of the correlator, for two temperatures in the range 2 - 3 GeV. Our calculations were done using the Highly Improved Staggered Quark action, and the strange and light quark masses were set respectively to their physical and nearly physical values, corresponding to meson masses $M_{\bar{s}s}=686$ MeV and $M_\pi=160$ MeV.