Are you referring to the point at which the airline collects passport and visa data for onward transmission to the USA? ICTS are but one of a number of aviation security companies. It could therefore be done by another company or the airline itself as part of the checkin process or even started as part of the online processes that are available from some airlines. BA, for example, collect that data through their "Manage my Booking" feature and have staff available to help at the airport if you don't do it earlier.
Maybe the quick way would be to phone Icelandair?