What is the difference between an LDT and an FDA-cleared or FDA-approved test?

FDA-cleared tests (via 510(k)) and FDA-approved tests (via PMA) undergo a formal FDA review of safety and effectiveness data before they can be marketed. This review includes analytical validation studies, clinical validation studies, and manufacturing quality system audits. FDA clearance/approval provides regulatory confidence but also requires the test manufacturer to invest $1–10 million and several years in the regulatory process before any patients benefit from the innovation. LDTs are validated by the laboratory itself under CLIA standards — a faster pathway that has historically allowed specialized laboratories to offer innovative tests more quickly. The trade-off: LDT validations are laboratory-internal (though peer-reviewed for Yenos), while FDA-reviewed tests have external validation. Both pathways are legal; the choice reflects the phase of the technology and the resources available.