If you have PDSMAN installed you can do a VERIFY of one PDS or several.
Partial output report from a PDSMAN VERIFY:
FCO110I VALIDATING PDS OUTDD=IN VOL=PRM222 DSN=aaaaaaaa.bbbbbbbb.cccccccc
FCO160U MEMBERS 237 TOTAL 237 IN-PLACE 0 MOVED
In the output report of the VERIFY you will see the PDS name and the number of members in that PDS.
The output report of the VERIFY can be searched with a REXX going after what is important to you, like the PDS name and number of members.