  In the QCD sum rules for the tetraquark (molecular) states, the higher
dimensional vacuum condensates play an important role in extracting the
tetraquark masses. We carry out the operator product expansion up to the vacuum
condensates of dimension-10 and observe that the vacuum condensates of
dimensions $6$, $8$ and $10$ have the same expressions but opposite signs for
the $C\gamma_5\otimes \gamma_\mu C$-type and $C\otimes \gamma_\mu C$ type
four-quark currents, which make their influences distinguishable, and they are
excellent channels to examine the vacuum saturation approximation. We introduce
a parameter $\kappa$ to parameterize the derivation from the vacuum saturation
or factorization approximation, and choose two sets parameters to examine the
influences on the predicted tetraquark masses, which can be confronted to the
experimental data in the future. In all the channels, smaller value of the
$\kappa$ leads to better convergent behavior in the operator product expansion,
which favors the vacuum saturation approximation.
