We recommend a 12 month calibration interval on most all of our instruments. This includes the TCP312A current probe. We do offer a service manual which covers performance verification and functional check that you can choose to utilize.
If you like you can contact service for a calibration quote.
Below you can find the contact information for our Service Department and someone will be happy to help:
Tektronix/Keithley Repair/Calibration:
Web: https://www.tek.com/en/service-quote
Email: rmarequest@tektronix.com