By David Colantonio, PhD

Most testing conducted in today’s clinical laboratories uses commercial reagent kits, manufactured and marketed by in vitro diagnostics companies. However, many new and existing biomarkers do not have commercial reagents available, resulting in the need for labs to develop and validate their own tests. These laboratory-developed tests (LDT) are primarily for internal use and are not distributed or sold to other labs. However, they present unique regulatory and validation challenges.

William Clarke, PhD clarified the evolving regulatory landscape for LDTs during yesterday afternoon’s symposium, Understanding and Implementing LDTs: What should we know? Clarke reviewed the role that the Centers for Medicare and Medicaid Services and the FDA play in LDTs.
Although FDA regulates ’ primary ingredients ’ for analyte-specific reagents--such as antibodies, nucleic acids, and enzymes--the agency does so to ensure the quality of these test components: it does not currently regulate LDTs themselves.

However, FDA recently concluded that  LDTs should be regulated at some level. In moving towards more oversight, three classes of risk have been established: Class I, low risk (e.g.spectrophotometer); Class II, moderate risk (e.g. Routine chemistry assays); and Class III, high risk（e.g. In vitro diagnostic multivariate index assays for cancer diagnosis). High risk  LDTs would require the strictest FDA oversight. Although many in the laboratory community agree that FDA should improve oversight for some LDTs --especially for high risk or direct-to-consumer tests--how FDA regulates LDTs  is a big cause for concern, Clarke noted.