One difference is the regulatory path to market and the regulatory body authorized to regulate them. Under the current U.S. regulatory framework molecular diagnostic tests (including genetic tests) have two compliant paths to market: the IVD path or the LDT path.
In vitro diagnostic devices (IVD) are developed and manufactured by device manufacturers under the Quality System Regulation (QSR) and unless exempt require premarket approval or 510(k) notification prior to sale and distribution. FDA has the authority to regulate devices that are distributed as IVD's as well as those that are distributed for "Investigational Use Only" (IUO) and for "Research Use Only" (RUO).
Laboratory Developed Tests (LDT's), also referred to as Homebrews, are diagnostic tests that are developed and manufactured by CLIA certified laboratories under their Quality Management System. These tests are developed by the lab for use only in that laboratory. CLIA laboratories develop the performance characteristis, perform the analytical validation for their LDT's and obtain licenses to offer them as diagnostic services. The Centers for Medicare & Medicaid Services (CMS) has the authority to regulate clinical laboratories and LDT’s under Clinical Laboratory Improvement Act of 1988 (CLIA ’88). CLIA ’88 established requirements that laboratories need to meet to perform various types of testing. These include certification and inspection.
Stay tuned for more on IVD's and LDT's.