Here is a code to get custom cell from index path
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:2 inSection:0];
YourCell *cell = (YourCell *)[tblRegister cellForRowAtIndexPath:indexPath];
For Swift
let indexpath = NSIndexPath(forRow: 2, inSection: 0)
let currentCell = tblTest.cellForRowAtIndexPath(indexpath) as! CellTest
For Swift 4 (for collectionview)
let indexpath = NSIndexPath(row: 2, section: 0)
let cell = self.colVw!.cellForItem(at: indexpath as IndexPath) as? ColViewCell