Resolution of Disagreement between Voluntary Consensus Standards and FDA Regulation

The US Food and Drug Administration’s (FDA) Center for Devices and Radiological Health uses many different standards to assist the approval of premarket proposals for medical devices. One of the benefits of using standards in this manner is to provide a set of common requirements and test protocols to the device manufacturer to ensure the safety and functionality of their product. The use of standards reduces the manufacturer’s need to “reinvent the wheel” for each new bench test, therefore saving the manufacturer both time and money. With the current trend toward international harmonization of standards, tests conducted in agreement with an international standard may be acceptable to several countries, therefore encouraging widespread usage of a specific product. However, there are occasions in which the FDA does not agree with certain provisions in a standard. As a result, the FDA aims to balance or resolve the issues that arise when there is discrepancy regarding the adequacy of a particular standard.

One approach employed by the FDA involves the recognition of only some provisions of a standard, or more commonly, disregarding the parts of a standard that are unacceptable to the FDA. In the case where a voluntary consensus standard conflicts with federal regulation, the FDA must follow its regulatory mandate instead of the consensus standard. For example, the Code of Federal Regulations (CFR) specifies a mandatory “performance standard for electrode lead wires and patient cables” (21 CFR 898). The federal performance standard, 21 CFR 898, ensures that “the distal connector of a patient cable (the connector located farthest from the patient) cannot be accidentally plugged into the AC power outlet.” Under 21 CFR 898.14 (b), the regulation outlines certain test requirements and test methods for verifying compliance with this federal performance standard. However, the voluntary consensus standard, ANSI/AAMI EC12:2000, section 5.3.2, set forth the verification test as inspection and does not require a test finger for verifying compliance. Because this clause of the EC12 standard disagrees with the federal regulation, the FDA supplementary information sheet indicates that this clause is not recognized. Therefore, the manufacturer is required to use the test methods set forth in 21 CFR 898.14 (b).

Another reason for the FDA to not accept a consensus standard is a discrepancy in scientific opinion of the technical justification used to validate the implementation of a standard. An example of this is the pressure band method used in clinical tests of noninvasive blood pressure (NIBP) monitors. The voluntary consensus standard, ANSI/AAMI SP10, has been used by many NIBP monitor manufacturers to validate the NIBP monitor against an invasive reference device. This standard allows the use of the “pressure band method.”¹ The FDA is concerned about potential insufficiencies in the scientific legitimacy of the pressure band method. These concerns stem from several technical issues. The FDA believes that there is some merit to the pressure band method if the width of the pressure band is not excessive. An appropriate response to this concern would be to propose a specification for an acceptable width of the pressure band, but the FDA is not ready to do so, given the lack of consensus regarding an appropriate pressure bandwidth. The consequence of allowing a wide pressure band is that the NIBP monitor would appear to be more accurate than clinical data demonstrates.

There are many advantages to be gained in technological innovation and product development by having the FDA’s regulatory requirements and international consensus standards as harmonized as possible. The FDA recognizes this fact and attempts to achieve this goal by sending representatives to participate in various standards development committees’ work. While this has been helpful in moving towards harmonized standards, the FDA realizes that much of the work must be determined by consensus via balloting. This means that there might be rare occasions in which there is discontinuity between the FDA’s requirements and the consensus standard that develops. Nevertheless, the FDA remains committed to working toward a goal of harmonization of standards within the capacity of the agency’s regulations.

¹ “If a subject device’s systolic pressure reading lies within the pressure band (ie, if the subject device’s reading is less than the maximum, but greater than the minimum, recorded by the invasive reference device), the difference between subject device and reference device is scored as “zero.” If the subject device’s systolic pressure reading lies outside the defined pressure band, only the distance between the subject device reading and the edge of the pressure band is scored as the difference between subject device and reference device.”

Source:

Charles Ho, Donald Jensen, Frank Lacy, Neal Muni, Sabina Reilly, Elias Mallis. “Use of standards in the review of medical devices.” Journal of Electrocardiology. Volume 38, Issue 4, Supplement, October 2005, Pages 171–174.