  Using the definition of uniformly perfect sets in terms of convergent
sequences, we apply lower bounds for the Hausdorff content of a uniformly
perfect subset $E$ of $\mathbb{R}^n$ to prove new explicit lower bounds for the
Hausdorff dimension of $E.$ These results also yield lower bounds for capacity
test functions, which we introduce, and enable us to characterize domains of
$\mathbb{R}^n$ with uniformly perfect boundaries. Moreover, we show that an
alternative method to define capacity test functions can be based on the
Whitney decomposition of the domain considered.
