How to judge an object Have been released

How to judge an object Have been released

How to judge an object Have been released?
If the UITableViewCell have been moved out screen, kkcell object will been
autoreleased by UITableView.
When the audiPlayer finished, program will run to " [kkcell
stopSpeakAmination]", this time
the program will crack.
How can i judge an object Have been released?
I also use
if(kkcell)
or
if(kkcell!=nil)
but still crack. my god:( Help me......
KKTableViewCell *kkcell;
(void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player
successfully:(BOOL)flag{
[kkcell stopSpeakAmination];
playing=NO;
}