Thread by @sbarnettARK

I've gotten a few questions about how the FDA regulates medical devices, chemical reagents, and diagnostic equipment.

Quick Thread 👇

First, understand there are two main regulatory pathways for diagnostic testing:

1. In-Vitro Diagnostic (IVD)
2. Laboratory Developed Test (LDT)

An IVD is an FDA-cleared diagnostic test sold as a self-contained kit.

thejournalofprecisionmedicine.com/wp-content/upl…

Companies wishing to sell IVDs must seek pre-market approval (PMA) from the FDA, which can take roughly 200 days. As I understand it, IVD's must be run on FDA-cleared diagnostic equipment, such as the NextSeq 550Dx, which is FDA-cleared and CE-marked (for Europe).

This way, FDA has end-to-end oversight of the diagnostic workflow. They must approve the kit (the IVD) and the machine that the IVD is run on (Dx-enablement).

This way, all a lab/hospital must do is buy both and they can run (and bill for) diagnostic tests.

Conversely, an LDT is a diagnostic test developed and operated by one lab in a central location. You do not need FDA-clearance on the reagents/equipment used in an LDT, so long as the lab is CLIA/CAP-certified.

fda.gov/medical-device…

You can use research-use-only (RUO) materials in an LDT, both reagents and equipment.

My point is that FDA-clearance is not required for equipment to be used in diagnostic procedures, so long as it's in a regulated, LDT-environment.

everycrsreport.com/files/20170411…

So, why seek FDA-clearance at all, then? If you wish to sell an IVD kit, yes it's necessary to obtain the PMA from FDA.

If you're an instrument-provider, an FDA-approval is helpful insofar as it allows for decentralized testing. As you may guess, an LDT is expensive.

So, having self-contained, FDA-cleared equipment lightens the burden on the lab/hospital so that they don't need to build an LDT on-site, all they need is your machine and they can start running IVDs.

academic.oup.com/ajcp/article/1…

I'll end by saying that FDA-cleared equipment needs to be matched by FDA-cleared IVDs. If there isn't a menu of IVDs, then the decentralization benefit to having approved equipment diminishes. You could argue FDA-clearance is helpful for a sales pitch, though.

Regulation is a tedious subject, so if you think I've misunderstood any nuances, please comment. Thanks!