Nihon Kohden Digital Health Solutions, LLC

During an inspection of your firm located in Irvine, CA from February 23, 2026 through February 24, 2026, an investigator from the United States Food and Drug Administration (FDA) determined that your firm manufactures the Next Generation NetKonnect software device, which is a Patient Physiological Monitor device with Arrhythmia detector and alarm (including ST-segment measurement and alarm). Under section 201(h) of the Federal Food, Drug, and Cosmetic Act (the Act), 21 U.S.C. § 321(h), these products are devices because they are 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.

Our inspection revealed that your Next Generation NetKonnect (NGNK) software device is adulterated under section 501(f)(1)(B) of the Act, 21 U.S.C. § 351(f)(1)(B), because your firm does not have an approved application for premarket approval (PMA) in effect pursuant to section 515(a) of the Act, 21 U.S.C. § 360e(a), or an approved application for an investigational device exemption under section 520(g) of the Act, 21 U.S.C. § 360j(g). The device is also misbranded under section 502(o) of the Act, 21 U.S.C. § 352(o), because your firm did not timely notify the agency of its intent to begin the introduction or delivery for introduction into interstate commerce for commercial distribution of the devices, as required by section 510(k) of the Act, 21 U.S.C. § 360(k). For a device requiring premarket approval, the notification required by section 510(k) of the Act, 21 U.S.C. § 360(k), is deemed satisfied when a PMA is pending before the agency. [21 CFR 807.81(b)(1)(i)]. The kind of information that your firm needs to submit in order to obtain approval or clearance for the devices is described on the Internet at http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/HowtoMarketYourDevice/default.htm. The FDA will evaluate the information that your firm submits and respond as appropriate.

Specifically, your firm’s Next Generation NetKonnect software devices are class II devices regulated under 21 CFR 870.1025 - Arrhythmia detector and alarm (including ST-segment measurement and alarm). Your device was most recently cleared as K220989 on July 29, 2022. On October 22, 2022, you implemented a software change to the device which included the ability to enable a Silence Alarms function. This introduced a device functionality that was not included in the originally cleared device. You completed a Regulatory Assessment for the modification in which you determined it would not significantly affect the safety and efficacy of the device, and that a Letter-to-File was appropriate. At decision point B2 of the assessment, “Is it a control mechanism, operating principles, or energy type change?” you selected “No.” You did not submit a premarket notification for this modification.

However, we disagree with this assessment because adding the Silence Alarms function is a change to a control mechanism of the device and we believe that “Yes” should have been selected, leading to “New 510(k).” The addition of a Silence Alarms function is a change to a control mechanism because it modifies the manner in which the user controls the device, which could result in the alarms not operating as the user intends. This change may result in missed alarms for life-threatening conditions that require immediate attention, leading to patient harm such as serious injury and/or death. As such, the modification of the device is a change or modification in the device that could significantly affect its safety or effectiveness and requires submission of a 510(k) under 21 CFR 807.81(a)(3)(i).

Additionally, the evidence indicates that you are distributing the NGNK software device with an unauthorized intended use that is different from that cleared under K220989. Namely, the labeling of your device indicates that the NGNK device is now intended to have “device-agnostic compatibility.” During the inspection, your firm’s management explained that “device-agnostic” describes NGNK’s ability to 1) run on any brand of commercial off-the-shelf computer and 2) support input from non-Nihon Kohden devices. However, your device was cleared under K220989 to support inputs from only other Nihon Kohden devices, and not from any device from other manufacturers. Therefore, “device-agnostic compatibility” is beyond the scope of the intended use that was cleared for the Next Generation NetKonnect. This change may introduce patient risks because of the use of additional input devices that have not been validated for compatibility with the NGNK software. Inadequate interoperability can result in incorrect vital sign measurements or loss of expected monitoring, which may result in delay of diagnosis or misdiagnosis. This is a major change or modification in the intended use of the device and requires submission of a 510(k) under 21 CFR 807.81(a)(3)(ii).

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.

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 CDRHEnforcement@fda.hhs.gov. Please include in the subject line, “CMS Case 727803” when replying. If you have any questions about the contents of this letter, please contact: Shaquenta Perkins at shaquenta.perkins@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 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.