Be careful that the Durbin-Watson statistic is only valid for autocorrelation of order one and models without lagged dependent as explanatory variable.
If you include the lagged dependent as explanatory variable, the test will be biased towards "no-rejection of H0=no-autocorrelation" so that you may wrongly conclude about the absence of autocorrelation when in reality it suffers from such problem.
The usual Durbin-Watson statistic is: $d=\Sigma_{t=2}^T(e_t-e_{t-1})^2/\Sigma_{t=1}^Te^2_t$
The alternative test is:$h=(1-d/2)*\sqrt{T/(1-T*Var(\hat{\beta_1)})}$ where $Var(\hat{\beta_1)})$ is the estimated variance of the regression coefficient of the lagged dependent variable and $d$ is the DW statistic.
The alternative test is distributed as a Chi-squared with degrees of freedom equal to the number of explanatory variables.
You can see that if a high autocorrelation coefficient of the lagged dependent makes the null hypothesis more easily rejected.