In the last two decades, the number of commercially available genetic tests is thought to have increased by more than 5,000%—from approximately 1,500 to an estimated 100,000 or more. This number only increases daily as US-based, Clinical Laboratory Improvement Amendments (CLIA)-certified laboratories commercialize new tests through the laboratory-developed test (LDT) pathway. LDTs are specialized tests performed only by certain labs and are regulated by Medicare through CLIA. This pathway, which is largely exempt from FDA premarket review, permits tests to come to market quickly and with little regulatory oversight.
The LDT pathway can be problematic because it does not require evidence from laboratories to support test claims. FDA previously identified problems with high-risk LDTs, ranging from a lack of appropriate controls yielding erroneous results to outright falsification of data. This makes it difficult for payers to know which tests to cover and for clinicians to know which tests are likely to help patients.