StatHat can send alerts directly to your PagerDuty account.
Note: PagerDuty has a StatHat integration guide on their site with step-by-step details on this process.
On your PagerDuty home page, go to "Services" then click on the "Add New Service" button.
Fill out the form with any name and escalation policy. Select the "Use our API directly" option.
Submit the form and you'll see a page that has a "Service API Key" field. Copy the value and go to the Alert destinations page on StatHat. Paste the key into the "Service Key" field on the PagerDuty form. Give your PagerDuty account a name and press the "Add" button.
Now you're all set to configure how alerts get sent to PagerDuty. You set the defaults on the Settings page.