  We investigate the quantum interference shifts between energetically close
states, where the state structure is observed by laser spectroscopy. We report
a compact and analytical expression that models the quantum interference
induced shift for any admixture of circular polarization of the incident laser
and angle of observation. An experimental scenario free of quantum interference
can thus be predicted with this formula. Although, this study is exemplified
here for muonic deuterium, it can be applied to any other laser spectroscopy
measurement of $ns-n'p$ frequencies of a nonrelativistic atomic system, via a
$ns\rightarrow n'p \rightarrow n"s $ scheme.
