Medical Testing Availability Act of 2013 - Amends the Federal Food, Drug, and Cosmetic Act with respect to labeling in the shipment or delivery of an in vitro diagnostic product for an investigation exempt from compliance with a performance standard or the requirement of premarket approval.

Declares that such a product whose labeling states "For Research Use Only. Not for use in diagnostic procedures." may not be deemed misbranded on the basis that its manufacturer or distributor: (1) sells the product to an end user who uses the product in a manner inconsistent with such statement, or (2) engages in business communications regarding the product with an end user.

Defines "business communications": (1) as oral, written, or electronic contact between a manufacturer or distributor of such a product and an end user regarding the product's functioning; and (2) includes any such contact consisting of technical support, customer service, assistance with the installation of such product, communication relating to ensuring the performance of the product, and other similar contacts.