As rule, "corrupted index" means some of the records were not documented in the index file. In this case you may consider this:
Let use suppose you have index on character field keyfld tag keyfld.
If index is corrupt, then these two action will give you different result:

coun for keyfld=""
sele keyfld from ... wher keyfld="" &&should give you more

Though it may be not quick for huge tables.



>Does anyone have a good, quick, reliable way to identify an index as being corrupt?
>
>I've got an app that has an occasional problem with index corruption - but am relying on the user's to spot something wrong. I want to be able to tell them something is wrong - or better yet - fix it before they notice.