Not to be mean; but, if you are asking you probably are not current.
Go PTF opt 5 (or dspptf. will show what PTFs you have TLyyjjj will give you the julian date of the last cumulative PTF (cumulative PTF have a julian date) (example I see on my system a TL13037 which was announced early Feb of 2013).
IBM’s website http://www-912.ibm.com/s_dir/sline003.nsf/ALLPSPS?OpenView&Start=1&Count=30&Expand=1#1 will give you latest PTF information. Look at group and hyper PTFs, not just cumulative PTFs.
Of course if you not on OS 6.1 or later, you probably can’t get ptfs for your system.