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# Don’t Exempt Drug Assays from 510(k): Sharfstein
- URL: https://www.fdaweb.com/dont-exempt-drug-assays-from-510-k-sharfstein/
- Published: 2017-05-17T12:00:00.000Z
- Updated: 2026-09-14T22:24:13.000Z
- Author: David McFarland
- Tags: Devices, #legacy-id-D5138711

A comment letter signed by former FDA principal deputy commissioner **Joshua Sharfstein** (now a professor at Johns Hopkins University) and five other medical school professors or researchers says that drug testing assays that are Class 2 medical devices and used for employment or insurance purposes should not be permitted to come to market without first submitting 510(k) premarket notification, including disclosure of device technological characteristics. The [letter](https://www.regulations.gov/contentStreamer?documentId=FDA-2017-N-1129-0033&attachmentNumber=1&contentType=pdf&ref=fdaweb.com) says the assays should be removed from proposed exemptions from the FDA premarket notification list because they fail to meet two specified criteria for an exemption: 

- **Changes will be readily detectable**. The letter says that for drug testing assays, a crucial technical specification is the cutoff value for a positive drug test that is measured in nanograms, a unit that does not meet FDA device exemption guidelines of changes needing to be “readily detectable by users by visual examination … or other routine testing.”
- **Changes will not increase the risk of injury or incorrect diagnosis**. A false positive result can cause significant harm in tests used for employment or insurance purposes, the comment letter says.