US FDA CDRH Warning Letters: A Review of 2024

By Sarah Fitzgerald

By reviewing relevant U.S. Food and Drug Administration (FDA) warning letters, manufacturers can better understand areas of frequent concern related to quality management systems (QMS) and regulatory affairs. This can allow companies to focus on areas of highest risk as they continually assess and improve their internal procedures and processes.

The FDA’s Center for Devices and Radiological Health (CDRH) issued 529 warning letters in 2024,[1] most related to drugs, tobacco products or food products. Of those, 8% (44)[2] were issued for medical devices.

Overview of medical device warning letters

Most warning letters include multiple issues, however, usually one appears to be the main issue, based either on the positioning within the warning letter (the first issue is usually considered to be the most significant) or the more detailed discussion within the warning letter. For a couple, a main reason was not apparent. There was a similar number of warning letters issued primarily for regulatory issues as for QMS issues in 2024. The table below summarizes what we at Emergo by UL believe are the main issues, based on a review of these warning letters.

Table 1. Apparent Main CDRH Warning Letter Issues

Apparent Main Issue	2023	2024
Primarily Regulatory Reasons
Devices without appropriate marketing submission / No marketing authorization	3	10
Devices with function/use that goes beyond what the authorized marketing submission covered, including due to device changes / Marketing authorization insufficient	8	9
Labeling Violations	1	0
Primarily Quality Management System (QMS) Reasons
Complaint investigation / medical device reporting (MDR) failures	2	1
Supplier/product controls	1	4
Corrective and Preventive Actions (CAPA) failures	3	6
Design/manufacturing validation process failures (including Risk Management)	2	8
Multiple QMS (Unable to determine what appears to be the main issue)	4	2
Other Issues
Testing Issues (Data integrity, clinical trial violations, etc.)	0	3

Details on medical device warning letters

To fully understand FDA’s concerns, we need to look beyond the primary issue, as most warning letters include multiple areas of concern. Tables 2a-d show all deficiency categories by warning letter. Note that for brevity, overall topics are grouped, so a warning letter may contain a different number of points that are provided, but the broad topics are addressed. Additionally, titles are minimized, therefore where something is noted as insufficient, this may range from no procedures covering a topic, to procedures not including certain required information, to the company not completely following a procedure.

Table 2a. Warning letters and categories of FDA concerns by warning letter

Warning Letter	694229	696569	698850	698214	697119	696362	695160	691601	692226	695683	695010
No Marketing Authorization						X
Marketing Authorization Insufficient									X
Insufficient Design Change Management			X
Labeling Insufficient											X
CAPA Procedure Insufficient		X	X	X	X			X	X		X
Complaint Procedure Insufficient	X										X
MDR Procedure Insufficient							X	X			X
Manufacturing / Infrastructure Validation Insufficient			X		X						X
Design Process, Controls, and/or Specifications	X	X		X	X				X		X
Design Validation / Verification	X				X		X	X	X
Insufficient Control of Non-Conformances					X				X
Insufficient Control of Final Device Acceptability			X		X				X	X	X
Insufficient Supplier / Incoming Product Controls	X								X	X
Failure to Maintain Record Files*
Insufficient Internal Audits
Insufficient Management Review
Insufficient Personnel Training					X
FDA Registration Missing
Shipping / Handling / Storage Insufficient
Recall / Correction Procedure Insufficient								X
Testing Issues

* Such as device master records, device history records, etc.

Table 2b. Warning letters and categories of FDA concerns by warning Lletter (continued)

Warning Letter	687970	687111	683606	676842	676849	677297	677092	679001	685606	681557	686915
No Marketing Authorization				X	X	X	X			X
Marketing Authorization Insufficient			X					X
Insufficient Design Change Management
Labeling Insufficient			X					X
CAPA Procedure Insufficient			X						X		X
Complaint Procedure Insufficient								X	X
MDR Procedure Insufficient								X	X
Manufacturing / Infrastructure Validation Insufficient			X
Design Process, Controls, and/or Specifications			X					X			X
Design Validation / Verification			X
Insufficient Control of Non-Conformances											X
Insufficient Control of Final Device Acceptability
Insufficient Supplier / Incoming Product Controls								X			X
Failure to Maintain Record Files*
Insufficient Internal Audits								X
Insufficient Management Review
Insufficient Personnel Training
FDA Registration Missing
Shipping / Handling / Storage Insufficient
Recall / Correction Procedure Insufficient									X
Testing Issues	X	X

* Such as device master records, device history records, etc.

Table 2c. Warning letters and categories of FDA concerns by warning letter (continued)

Warning Letter	687035	678344	673150	675673	679404	676367	678281	665159	671243	677545	677753
No Marketing Authorization		X	X			X
Marketing Authorization Insufficient				X	X		X	X		X	X
Insufficient Design Change Management										X
Labeling Insufficient		X
CAPA Procedure Insufficient			X			X	X			X
Complaint Procedure Insufficient						X	X			X
MDR Procedure Insufficient						X	X		X
Manufacturing / Infrastructure Validation Insufficient							X			X
Design Process, Controls, and/or Specifications	X		X			X				X
Design Validation / Verification			X		X		X			X
Insufficient Control of Non-Conformances
Insufficient Control of Final Device Acceptability				X
Insufficient Supplier / Incoming Product Controls			X		X				X	X
Failure to Maintain Record Files*	X						X
Insufficient Internal Audits
Insufficient Management Review
Insufficient Personnel Training
FDA Registration Missing		X
Shipping / Handling / Storage Insufficient
Recall / Correction Procedure Insufficient								X	X
Testing Issues

* Such as device master records, device history records, etc.

Table 2d. Warning letters and categories of FDA concerns by warning letter (continued)

Warning Letter	675069	673465	669904	667193	671249	678042	677524	676605	687033	692084
No Marketing Authorization				X
Marketing Authorization Insufficient	X						X
Insufficient Design Change Management					X	X	X			X
Labeling Insufficient				X
CAPA Procedure Insufficient			X		X	X			X	X
Complaint Procedure Insufficient				X			X			X
MDR Procedure Insufficient					X		X		X	X
Manufacturing / Infrastructure Validation Insufficient
Design Process, Controls, and/or Specifications					X	X
Design Validation / Verification			X		X				X	X
Insufficient Control of Non-Conformances						X
Insufficient Control of Final Device Acceptability
Insufficient Supplier / Incoming Product Controls				X				X
Failure to Maintain Record Files*				X
Insufficient Internal Audits				X
Insufficient Management Review				X
Insufficient Personnel Training
FDA Registration Missing							X
Shipping / Handling / Storage Insufficient
Recall / Correction Procedure Insufficient								X		X
Testing Issues		X

* Such as Device Master Records, Device History Records, etc.

There were a few interesting considerations from our review of 2024 warning letters that are summarized below:

Four warning letters related primarily to unauthorized products for cleaning, sanitizing or disinfecting continuous positive airway pressure (CPAP) machines. This suggests there was particular scrutiny of such products.

Four warning letters appeared to address a manufacturer/specification developer, contract manufacturer, and two convenience kit manufacturers where the original 510(k) (K103830) covered only one size of syringes but multiple sizes were being manufactured or placed into a convenience kit. It seems likely that one of these facilities was first inspected and the others subsequently inspected in part to follow up on this issue.

Two warning letters issued by CDRH were not for device manufacturers, but rather for testing laboratories working with animals.

One warning letter noted that the manufacturer was claiming and labeling the device for research use only, but the evidence from certain marketing information and sales suggested that the device was not being sold for research use only.

Risk management was a major topic of discussion related back to many of the violations this year, and was mentioned in many of the warning letters, including for the initial validation of device design and noting that risk management was not updated either in alignment with the procedure or alignment with ISO 14971 when compliance with the standard was claimed.

Last year (2023), several warning letters emphasized unique device identification (UDI), including one where that was the sole reason for the warning letter. While at least two of the warning letters this year did include a discussion of UDI, none were issued solely or primarily for UDI violations.

Categorization of the warning letters

Table 3 provides a summary of all deficiencies and calculates a percentage of the total of the medical device-related warning letters.

Table 3. Warning letters and categories overview

Warning Letter	Overall	%
No Marketing Authorization	10	23%
Marketing Authorization Insufficient	11	26%
Insufficient Design Change Management	6	14%
Labeling Insufficient	5	12%
CAPA Procedure Insufficient	19	44%
Complaint Procedure Insufficient	7	16%
Medical Device Reporting (MDR) Procedure Insufficient	12	28%
Manufacturing / Infrastructure Validation Insufficient	6	14%
Design Process, Controls, and/or Specifications	15	35%
Design Validation / Verification	14	33%
Insufficient Control of Non-Conformances	4	9%
Insufficient Control of Final Device Acceptability	6	14%
Insufficient Supplier / Incoming Product Controls	11	26%
Failure to Maintain Record Files*	3	7%
Insufficient Internal Audits	2	5%
Insufficient Management Review	1	2%
Insufficient Personnel Training	1	2%
FDA Registration Missing	2	5%
Shipping / Handling / Storage Insufficient	0	0%
Recall / Correction Procedure Insufficient	4	9%
Testing Issues	4	9%

* Such as Device Master Records, Device History Records, etc.

Table 4 summarizes the most frequently cited categories for 2023 and 2024. The same categories are generally of the most concern for both years, although with the greater number of warning letters in 2024 there appears to be less concentration of issues.

Table 4. Most frequently cited categories in warning letters

Warning Letter	2023	2024
No Marketing Authorization
Marketing Authorization Insufficient	25 - 50%	25 - 50%
Insufficient Design Change Management
Labeling Insufficient	25 - 50%
CAPA Procedure Insufficient	>50%	25 - 50%
Complaint Procedure Insufficient	25 - 50%
Medical Device Reporting (MDR) Procedure Insufficient	>50%	25 - 50%
Manufacturing / Infrastructure Validation Insufficient	25 - 50%
Design Process, Controls, and/or Specifications	25 - 50%	25 - 50%
Design Validation / Verification	25 - 50%	25 - 50%
Insufficient Control of Non-Conformances
Insufficient Control of Final Device Acceptability
Insufficient Supplier / Incoming Product Controls	25 - 50%	25 - 50%
Failure to Maintain Record Files*	25 - 50%
Insufficient Internal Audits
Insufficient Management Review
Insufficient Personnel Training
FDA Registration Missing
Shipping / Handling / Storage Insufficient
Recall / Correction Procedure Insufficient
Testing Issues

* Such as Device Master Records, Device History Records, etc.

Concluding remarks

Manufacturers should pay careful attention to the procedures and processes within the categories that the FDA has found frequently deficient (as shown in Table 4) as they periodically assess these while working toward continual improvement.

Our Emergo consultants are available to assist with QMS and regulatory considerations related to medical devices.

[1] Posted warning letters as of January 24, 2025.

[2] Note: The FDA CDRH annual report noted there were 44 warning letters issued, but a search of the FDA database on January 24. 2024 only located 43 as it may take a few months before posting on the FDA database. This report is based on the 43 that could be analyzed.

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US FDA CDRH Warning Letters: A Review of 2024

Overview of medical device warning letters

Details on medical device warning letters

Categorization of the warning letters

Concluding remarks

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US FDA CDRH Warning Letters: A Review of 2024

Overview of medical device warning letters

Details on medical device warning letters

Categorization of the warning letters

Concluding remarks

Clinical Data in Support of U.S. FDA 510(k) Submissions

FDA QSR Consulting (21 CFR 820) for Medical Device Manufacturers

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