  We derive expressions for the universal contribution to the specific heat of
a three-dimensional metal near a zero-temperature phase transition with dynamic
exponent $z=2,3$, or 4. The results allow a quantitative comparison of theory
to data. We illustrate the application of our results by analyzing data for
Ce$_{1-x}$Lu$_x$Cu$_2$Si$_2$, which has been claimed to be near a quantum
critical point.
