Is there a way to find out Indexer is still running except an exception?

I'm trying using different index-based methods in my plugin but sometimes it drops out with this exception:

IndexNotReadyException

This results in bad user experience for my users 'cause functionion of the plugin is not reliable and I need to display inconsistent state somehow. I wish there'd be a way just to ask if indexer is still running  - then I would just do not display content at all.