  For any 4d N=2 SCFT, there is a subsector described by a 2d chiral algebra.
The vacuum character of the chiral algebra reproduces the Schur index of the
corresponding 4d theory. The Macdonald index counts the same set of operators
as the Schur index, but the former has one more fugacity than the latter. We
conjecture a prescription to obtain the Macdonald index from the chiral
algebra. The vacuum module admits a filtration, from which we construct an
associated graded vector space. From this grading, we conjecture a notion of
refined character for the vacuum module of a chiral algebra, which reproduces
the Macdonald index. We test this prescription for the Argyres-Douglas theories
of type $(A_1, A_{2n})$ and $(A_1, D_{2n+1})$ where the chiral algebras are
given by Virasoro and su(2) affine Kac-Moody algebra. When the chiral algebra
has more than one family of generators, our prescription requires a knowledge
of the generators from the 4d.
