Should/Could the FDA Regulate Whole Slide Imaging as a Class II Device?

| August 16, 2012

Frequent readers and those who have heard me speak publicly on the topic of government regulation and oversight of whole slide imaging recognize that I really do not think that manufacturers need a stamp of approval from the FDA to the effect that "FDA Approved for Primary H&E Diagnosis" on their claims and marketing materials.  Perhaps manufacturers think they do because their sense is that more and more pathologists will in fact buy the technology if it indeed has that stamp of approval that the agency concerned with regulating food, drugs and devices in the bests interests of patient safety and assuring apprropriate risk:benefit ratios says it is OK to use for primary diagnosis.

With that being said, we now know it is unlikely that these devices will be regarded as Class I devices (see below).  As they will not be regarded as Class I, I think the device or instrument in question is then regarded as a Class III device requiring pre-market approcal "for which insufficient information exists to assure safety and effectiveness solely through the general or special controls sufficient for Class I or Class II devices" (see below according to The FDA Class Classification).

Why then could whole slide imaging devices/systems not be regarded as Class II?  

FDA_salmonellaLet's assume with whole slide imaging is regarded as being higher risk for potential injury or harm than a Class I device historically and essentially, according to the definition, "for which general controls alone are insufficient to assure safety and effectiveness, and existing methods are available to provide such assurances. In addition to complying with general controls, Class II devices are also subject to special controls. A few Class II devices are exempt from the premarket notification. Special controls may include special labeling requirements, mandatory performance standards and postmarket surveillance. Devices in Class II are held to a higher level of assurance than Class I devices, and are designed to perform as indicated without causing injury or harm to patient or user."

Don't we actually have this with digital pathology today?  Special labeling requirements, i.e. certain stains from certain vendors for purposes of prognostic and therapeutic testing (ER, PR, HER2, Ki-67), mandatory performance standards, i.e. constant review, quality assurance, correlations and peer reviews in surgical pathology, a degree of scrutiny unrivaled in any specialty in medicine in terms of self-auditing ourselves and lastly, postmarket surveillance. Here we have 100s of papers written with 1000s of cases studied in peer-reviewed literature and decades worth of experience as a specialty.  In a recent survey on digital pathology conducted, 20% of respondents  mentioned using digital pathology for primary clinical diagnosis.

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In a more recent follow up post on the survey a couple of weeks ago, there was discussion of the best use cases for digital pathology.  They are what this survey affirms, in my opinion, image analysis, i.e. ER/PR/HER2 scoring and second opinions/consultations/expert reviews.

Unless your practice is in New York and you are in Aspen, in which case you probably either need to move your lab or move yourself, I do not understand the need for "Primry H&E Diagnosis" by digital pathology.  The instances I can think of include in-office laboratories and the occassional times when you are in Aspen, 1000s of miles from your histology laboratory on a temporary basis.  Given the number of times of these occurrences and the number of slides produced and read in these types of practice settings, it is a very small percentage of the estimated tens of millions of slides produced annually in the United States.

Nonetheless, assuming we recognize more risk than the microscope itself in this instance (a Class I exempt device) and we are held to "special controls may include special labeling requirements, mandatory performance standards and postmarket surveillance", it would seem logical that whole slide imaging devices/systems be regarded as Class II and allow the market and practioners to define the nuances of these controls, standards and postmarket surveillance conditions.

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FDA Device Class Classification (as cut and pasted from Wikipedia):

The Food and Drug Administration has recognized three classes of medical devices based on the level of control necessary to assure the safety and effectiveness of the device.  The classification procedures are described in the Code of Federal Regulations, Title 21, part 860 (usually known as 21 CFR 860).

Class I: General controls

Class I devices are subject to the least regulatory control. Class I devices are subject to "General Controls" as are Class II and Class III devices. General controls include provisions that relate to adulteration; misbranding; device registration and listing; premarket notification; banned devices; notification, including repair, replacement, or refund; records and reports; restricted devices; and good manufacturing practices. Class I devices are not intended for use in supporting or sustaining life or to be of substantial importance in preventing impairment to human health, and they may not present a potential unreasonable risk of illness or injury. Most Class I devices are exempt from the premarket notification and/or good manufacturing practices regulation. Examples of Class I devices include elastic bandages, examination gloves, and hand-held surgical instruments.

Class II: General controls with special controls

Class II devices are those for which general controls alone are insufficient to assure safety and effectiveness, and existing methods are available to provide such assurances. In addition to complying with general controls, Class II devices are also subject to special controls. A few Class II devices are exempt from the premarket notification. Special controls may include special labeling requirements, mandatory performance standards and postmarket surveillance. Devices in Class II are held to a higher level of assurance than Class I devices, and are designed to perform as indicated without causing injury or harm to patient or user. Examples of Class II devices include powered wheelchairs, infusion pumps, and surgical drapes.

Class III: General controls and premarket approval

A Class III device is one for which insufficient information exists to assure safety and effectiveness solely through the general or special controls sufficient for Class I or Class II devices. Such a device needs premarket approval, a scientific review to ensure the device's safety and effectiveness, in addition to the general controls of Class I. Class III devices are usually those that support or sustain human life, are of substantial importance in preventing impairment of human health, or which present a potential, unreasonable risk of illness or injury. Examples of Class III devices which currently require a premarket notification include implantable pacemaker, pulse generators, HIV diagnostic tests, automated external defibrillators, and endosseous implants.

 


Category: Digital Pathology News, Histology, Pathology News

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