FDA issued a draft guidance to clarify Investigation or Research Use Only IVDs that do not require IDEs. The comment period ends August 30, 2011. Question 7 indicates standalone software can handled in this way and states: Yes, software that is a stand-alone IVD product, or a component of or an accessory to another IVD product, which is labeled in accordance with 21 CFR 809.10(c)(2), may be marketed for research or investigational use to entities conducting research or investigations with the software. Such software is subject to the same limitations on promotion and marketing as other IVD products labeled RUO or IUO. The full guidance is at the link provided.