  QCD sum-rule studies have been useful to understand and get an insight on the
structure of exotic states, such as tetraquark systems. Moreover, the majority
of these studies are performed only at leading-order (LO) within the light
tetraquarks systems picture, overlooking the effects of higher order
corrections, thus motivating our analysis. Our study focused on the effects of
next-to-leading order (NLO) contributions to the mass estimates of the lightest
tetraquark state ($J^{PC} = 0^{++}$), the so-called $\sigma$ or $f_{0}(500)$,
using ratios of QCD Laplace sum-rules. A variety of different models were used,
which included multiple resonances and width effects, resulting in a final mass
prediction of $0.52\,\text{GeV}< m_{\sigma}< 0.77\,\text{GeV}$. Even though the
ratios of sum-rules demonstrated some insensitivity under superficially large
NLO contributions, they added the beneficial feature of canceling the
dependence on the anomalous dimension. Our findings were in good agreement with
patterns found in Chiral Lagrangian studies regarding the four-quark structure
of the $\sigma$ state, including the relative coupling strengths within the
multiple resonance analysis.
