Medical Device and Diagnostic Regulation


The FDA is very specific in how they define the various types of products. In this section we discuss: 

Medical Devices: do not deliver their effect through chemical means and are not dependent on being metabolized

Diagnostics: used to determine or quantify the presence of a condition or analyte

Diagnostics come in two forms:

In Vitro Diagnostics: this is when you analyze specimens taken from the human body

Analyte Specific Reagents: this is the active ingredient of an in-house test, for example reagents used to identify or quantify a chemical substance or ligand in a biological specimen


Medical devices and diagnostics fall into three categories, depending on the nature of the product. The categories are defined as:



Class I: Low risk and subject to the least regulatory controls (e.g. dental floss)

Class II: Higher risk and require reasonable assurance of safety and effectiveness (e.g. condoms)

Class III: Highest risk and typically required FDA approval before being marketed (e.g. replacement heart valves)


Class I: Diagnostic for a specific substance or ligand

Class II: Diagnostic/reagent for blood banking

Class III: Diagnostic/reagent used in a test for a condition that has a high probability of a fatal outcome


Process Overview

Medical devices & diagnostics are regulated the same way. If there is a similar device on the market, and you plan to have the same indications and claims as that device, or you can prove your new claims with alternatives such as animal studies, then you can follow a 510(k) Regulatory Pathway. This means:

  • Review time: ~5 months (In 2011-2015, the average approval time was 151 days)

  • Costs: 2017 Application Fee is $4690 (with a discount for small businesses)

  • Requires proving substantial equivalence to an existing medical device or diagnostic

However, if there is no similar device, or you are seeking new indications or new claims that require proof via human trials, then you need to use a PMA Regulatory Pathway. This mean:

  • Approval time: ~1 year after completing clinical studies (5-7 years is typical from study start)

  • Costs: 2017 Application Fee is $234,495 (with a discount for small businesses) + study costs

  • Requires special manufacturing controls and an FDA site investigation

  • Requires supplements for any later product changes (180 day approval time + $35k fee)

Changing your approved device or diagnostic 

After you have a device on the market, you’ll have to go through a regulatory process every time you want to make any changes to your device. Depending on the nature of your change, you will either need a letter to file, or a new 510(k).

First, if the change is due to a recall or corrective action, or you are making a change in materials, see 510(k) requirements for Proposed Fixes to Devices Undergoing Recall.


Label Changes

If you want to make a label change, then a letter to file is sufficient if you are:

  • Changing warnings and precautions

  • Clarifying instructions to insure safer or more effective use

  • Changing the packaging or expiration dating

For all other reasons, such as changing the indications for use or adding/deleting a contraindication, you will need to file a 510(k).


Technology or Performance Changes

If you are changing the technology or performance of your device, you will need a 510(k) if you are changing the:

  • Control mechanism

  • Operating principle

  • Energy source (e.g. going from manual to electric power)

  • Sterilization process in way that affects the performance specification or decreases safety & efficacy

  • Material type that comes into contact body tissues or fluids and requires testing per the requirements of ISO 10993-1

  • Material supplier when the material is not ordered to a specification

When changing the following factors, you only need to submit a 510(k) if you affect the indications for use, require clinical data to establish safety and efficacy (S&E), or have design validation raise new S&E issues. Otherwise, a letter to file is sufficient.

  • Environmental specifications

  • Dimensional specifications

  • Performance specifications

  • Ergonomics of the patient user interface

  • Software or firmware

  • Material formulation

  • Material supplier when the material is ordered to a specification

If you are not changing the label, technology, performance or materials, or for any issues not listed above, then a letter to file is advised.