Sort or filter on ISO

Usually, the photos that need attention for noise reduction are those taken with high ISO.  How high varies a bit with the camera, but generally I want to consider applying noise reduction at ISO 1600 or higher and sometimes even ISO 800.  And the best time to apply noise reduction is at the very start of processing.

Given these considerations it seems odd that LR does not provide any help in locating the high ISO images in a collection or folder.   Ability to sort on ISO would be extremely useful; alternatively, a way to filter on high ISO could serve much the same need.  Neither of these options would seem to present much difficulty since ISO is recorded in the EXIF information.