WARNING LETTER
Koven Technologies, Inc.
MARCS-CMS 734643 —
July 21, 2026
Delivery Method:
VIA Electronic Mail
Product:
Medical Devices
Recipient:
Recipient Name
Heather S. Bell
Recipient Title
President
Koven Technologies, Inc.
477 N. Lindbergh Blvd. Ste. 220
Saint Louis
,
MO
63141
United States
(b)(6), (b)(7)(C)
Issuing Office:
Center for Devices and Radiological Health
United States
WARNING LETTER
CMS # 734643
July 21, 2026
Dear Ms. Bell:
During an inspection of your firm located in Saint Louis, MO, conducted from February 2, 2026, through February 6, 2026, an investigator from the United States Food and Drug Administration (FDA) determined that your firm manufactures and/or markets the Bidop 3 Doppler. Under section 201(h) of the Federal Food, Drug, and Cosmetic Act (the Act), 21 U.S.C. § 321(h), this product is a device because it is intended for use in the diagnosis of disease or other conditions or in the cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of the body.
Quality Management System Regulation Violation(s)
This inspection revealed that these devices are adulterated within the meaning of section 501(h) of the Act, 21 U.S.C. § 351(h), in that the methods used in, or the facilities or controls used for, their manufacture, packing, storage, or installation are not in conformity with the current good manufacturing practice requirements of the Quality Management System Regulation found at Title 21, Code of Federal Regulations (CFR), Part 820. We received responses from Heather Bell, President, on February 27, 2026; April 17, 2026; and May 28, 2026, concerning our investigator’s observations noted on the Form FDA 483 (FDA 483), List of Inspectional Observations, which was issued to your firm. We address these responses below, in relation to each of the noted violations. These violations include but are not limited to the following:
1. Failure to document procedures to control design and development changes, and determine the significance of these changes to function, performance, usability, safety and regulatory requirements for the medical device and its intended use, as required by ISO 13485:2016 Clause 7.3.9.
Specifically, your firm failed to follow procedure 1-SOP-014, Design Control, which states, “All design changes must be identified, documented, where appropriate validated, reviewed and approved before the changes may be implemented.” Additionally, your firm failed to follow procedure 2-SOP-010, Device Registration, Submission and Notification, which requires that once a device or process is changed,
(b)(4)
. Your firm did not document design and development changes related to expanding the indications for use of the Bidop 3 (K954397) to include a fetal application which was not cleared as an intended use. During the inspection, the Bidop 3 operations manual noted the indications for use include detection of fetal heart sounds. Your firm has not provided documentation of:
A. The review and approval of design change documentation, including:
i. Specific modifications made to the device (hardware, software, or performance specifications) to support fetal use.
ii. Validation data demonstrating the device's safety and effectiveness for fetal applications.
B. An evaluation to determine whether the change in indications for use (from non-fetal to fetal application) required a new 510(k) submission.
C. The date when distribution was initiated for the Bidop 3 as a Fetal Doppler.
The adequacy of your firm’s responses cannot be determined at this time. Your corrective actions are in progress. Your responses mention that your firm notified customers via certified mail to suspend the use of fetal probes with Bidop 3 doppler units and that you conducted a 21 CFR 806 reportability assessment. FDA received your 806 report on 03/06/2026 and it is being processed under RES ID: 98556. The recall is on-going.
2. Failure to document one or more processes for risk management in product realization and determine, as appropriate, quality objectives and requirements for the product, as required by ISO 13485:2016 Clause 7.1.
Specifically, your firm’s risk management analysis for your devices revealed inadequate hazard identification and risk analysis as evidenced by the two (2) fetal dopplers below:
A. Product ES-100V3 (Bidop 3), 510(k) K954397, cleared March 29, 1996: The risk management report (Document
(b)(4)
, dated September 3, 2025) was revised to include an indication for use as a fetal heart rate doppler, according to management. However, this report fails to evaluate risks to the fetus, despite the device being labeled for determining fetal heart rate and sounds.
B. Product Bidop 7, 510(k) K201114, cleared January 5, 2021: The risk management report (Document
(b)(4)
, dated February 5, 2020) contains no evaluation of risks to the fetus, despite the device's indication for use, which includes displaying bi-directional velocity waveforms, numerical data, and fetal heart rate with a heartbeat indicator.
The fetus is directly exposed to ultrasound energy and is the primary patient population for these devices. Failure to evaluate fetal-specific hazards (e.g., thermal effects, acoustic exposure, diagnostic accuracy affecting clinical decisions) represents inadequate risk analysis for the devices' intended use. Use of doppler ultrasound devices for fetal monitoring entails additional risks as compared to their use for blood flow monitoring. Fetal tissue is more vulnerable to prolonged or inappropriate ultrasound exposure than adult tissue. Additionally, improper use of the doppler for fetal monitoring may cause misinterpretation of maternal heartbeats or placental blood flow as fetal heartbeat, creating false reassurance. This can result in missed fetal distress signals, delayed care, and severe outcomes including fetal death. Conversely, failure to correctly detect a fetal heartbeat may cause anxiety and unnecessary clinical interventions.
Therefore, the risk analysis of the fetal doppler ultrasound device should clearly assess these specific risks associated with use of the device for fetal monitoring as discussed above and specific hazards including fetal distress or death due to misinterpretation, and delayed care.
The adequacy of your firm’s responses cannot be determined at this time. Your corrective actions are in progress. Your firm completed a review of the risk management files for the Bidop 7 to address hazards consistent with the cleared intended use. However, your firm did not provide supporting documentation.
3. Failure to establish criteria for the evaluation and selection of suppliers, as required by ISO 13485:2016 Clause 7.4.1.
Specifically, your firm has not established adequate criteria for the evaluation and selection of your approved suppliers based on their ability to provide product that meets requirements, the performance of the supplier, and the effect of the purchased product on the quality of the device. For example,
A. Your firm holds 25 510(k) clearances for devices designed and manufactured by a contract manufacturer. During the inspection the Bidop 3 Doppler was found to have indications for use that differ from those in the cleared 510(k). The indications for use were changed from non-fetal to fetal application. This design change was implemented by your contract manufacturer and your firm does not have documentation of this change nor could your firm identify when this change occurred. The quality agreement between your firm and your contract manufacturer (Section 5.5, Labeling) requires that any changes to labeling
(b)(4)
. This undocumented change represents a failure to ensure that
(b)(4)
labeling changes as is established in your quality agreement. Furthermore, the quality agreement fails to
(b)(4)
design changes beyond labeling.
B. Per procedure 1-SOP-020,
(b)(4)
supplier approval criteria include requirements that must be met such as having a quality agreement, product inspection, and site assessment. There is no documentation that a site assessment (supplier audit) has been conducted for the contract manufacturer, a
(b)(4)
supplier which your firm’s procedure defines as “Highest/Critical Impact.”
The adequacy of your firm’s responses cannot be determined at this time. Your corrective actions are in progress. We acknowledge that one of your corrective actions is that your firm amended the quality agreement with your contract manufacturer to include comprehensive design change notifications, access to change logs, and audit rights commensurate with the planned transfer of the 510(k)’s to your supplier. You mention that CAPA CA2026-3 is complete; however, it is in the effectiveness stage and your firm mentioned open corrective actions. As such, please ensure to keep the CAPA open and documented while you are completing all the steps of a CAPA.
4. Failure to maintain records of the review, evaluation, and investigation for any complaints involving the possible failure of a device, labeling, or packaging to meet any of its specifications, as required by 21 CFR 820.35(a).
Specifically, your firm failed to evaluate returned devices related to device failures affecting performance and reliability as complaints. Between January 1, 2024, and December 31, 2025, approximately
(b)(4)
Returned Goods Authorizations (RGAs) were issued for device returns. The investigator reviewed 29 completed RGA forms coded as "
(b)(4)
" and found that 13 of these forms reported device failures but were not evaluated as complaints. Your firm did not consider these reports as complaints and did not initiate or complete a complaint form as required by your complaint procedure, SOP 4-SOP-050 (Customer Complaint). This procedure defines a complaint as "Any written, electronic, or oral communication that alleges deficiencies related to the identity, quality, durability, reliability, usability, safety, or performance of a medical device that has been released from the organization's control or related to a service that affects the performance of such medical devices.” For example:
RGA
Number
Date
Device
Code
Failure/Inspection
10923
6/26/2024
Bidop 7
(b)(4)
The doppler memory has been cleared and when it is turned off and on, it comes up memory store #11 or memory store #1. The doppler should go straight to the LCD screen.
11061
9/18/2024
Bidop 3
(b)(4)
No consistent waveform with toe pressure sensor
11211
1/8/2025
Bidop 3
(b)(4)
Out of box failure
11509
6/27/2025
CRP-20H, cardiovascular probe
(b)(4)
Not picking up vascular flow
11402
4/22/2025
Aneroid Sphygmomanometer
(b)(4)
Doesn’t measure correctly on toe
The adequacy of your firm’s responses cannot be determined at this time. Your corrective actions are in progress. Your firm provided the training records showing the employees trained to the updated procedures; however, you did not provide specifics on the evaluation conducted for the employees to confirm they understood the updates. Please provide this information.
Your firm should take prompt action to address any violations identified in this letter. Failure to adequately address this matter may result in regulatory action being initiated by the FDA without further notice. These actions include, but are not limited to, seizure, injunction, and civil money penalties.
Other federal agencies may take your compliance with the FD&C Act and its implementing regulations into account when considering the award of federal contracts. Additionally, should FDA determine that you have Quality Management System Regulation violations that are reasonably related to premarket approval applications for Class III devices, such devices will not be approved until the violations have been addressed. Should FDA determine that your devices or facilities do not meet the requirements of the Act, requests for Certificates to Foreign Governments (CFG) may not be granted.
Please notify this office in writing within fifteen business days from the date you receive this letter of the specific steps your firm has taken to address the noted violations, as well as an explanation of how your firm plans to prevent these violations, or similar violations, from occurring again. Include documentation of the corrections and/or corrective actions (which must address systemic problems) that your firm has taken. If your firm’s planned corrections and/or corrective actions will occur over time, please include a timetable for implementation of those activities. If corrections and/or corrective actions cannot be completed within fifteen business days, state the reason for the delay and the time within which these activities will be completed. Your firm’s response should be comprehensive and address any violations included in this Warning Letter. If you believe that your products are not in violation of the FD&C Act, include your reasoning and any supporting information for our consideration as part of your response.
Your firm’s response should be sent via email to Melissa Michurski, Establishment Assessment Team 2, Assistant Director at CDRHEnforcement@fda.hhs.gov. Please include in the subject line, “CMS Case [734643]” when replying. If you have any questions about the contents of this letter, please contact: Ashley Mutawakkil, Compliance Officer, Ashley.Mutawakkil@fda.hhs.gov.
Finally, you should know that this letter is not intended to be an all-inclusive list of the violations at your firm’s facility. It is your firm’s responsibility to ensure compliance with applicable laws and regulations administered by FDA. The specific violations noted in this letter and in the Inspectional Observations, FDA 483, issued at the close of the inspection may be symptomatic of serious problems in your firm’s manufacturing and quality management systems. Your firm should investigate and determine the causes of any violations and take prompt actions to address any violations and bring the products into compliance.
Sincerely,
/S/
CAPT Cesar A. Perez, PhD, USPHS
Acting Deputy Director
Office of Regulatory Programs
Office of Product Evaluation and Quality
Center for Devices and Radiological Health
Content current as of:
08/04/2026
Regulated Product(s)
Medical Devices