Digital Pathology Blog

The second most popular question people ask me as a consultant in digital pathology is,

Have there been any updates to the FDA’s position on Digital Pathology?

No, but there are safe and effective ways to use digital pathology in a clinical setting today.   The FDA regulates what digital pathology manufacturers can claim or say their technology is used for, not what a pathologist or a hospital does with digital pathology. Safe and effective uses of digital pathology are available today that can benefit hospitals, labs, pathologists, medical students, residents, patients and more.  Examples include tumor boards, consultations, intra-operative, education, archival, decision support, peer review, quality assurance, and manual or automated image analysis.

You are thinking…

Blah, blah, blah, blah.. and blah. I’ve heard all of this before!  Tell me when will this be ready and safe for primary diagnosis?

Okay, but let me warn you… you asked for it! CLIA is who regulates laboratory use of digital pathology.  So, let’s see what CLIA says:

Sec. 493.1253  Standard: Establishment and verification of performance
specifications

    (a) Applicability. Laboratories are not required to verify or
establish performance specifications for any test system used by the
laboratory before April 24, 2003.
    (b)(1) Verification of performance specifications. Each laboratory
that introduces an unmodified, FDA-cleared or approved test system must
do the following before reporting patient test results:
    (i) Demonstrate that it can obtain performance specifications
comparable to those established by the manufacturer for the following
performance characteristics:
    (A) Accuracy.
    (B) Precision.
    (C) Reportable range of test results for the test system.
    (ii) Verify that the manufacturer's reference intervals (normal
values) are appropriate for the laboratory's patient population.
    (2) Establishment of performance specifications. Each laboratory
that modifies an FDA-cleared or approved test system, or introduces a
test system not subject to FDA clearance or approval (including methods
developed in-house and standardized methods such as text book
procedures, Gram stain, or potassium hydroxide preparations), or uses a
test system in which performance specifications are not provided by the
manufacturer must, before reporting patient test results, establish for
each test system the performance specifications for the following
performance characteristics, as applicable:
    (i) Accuracy.
    (ii) Precision.
    (iii) Analytical sensitivity.
    (iv) Analytical specificity to include interfering substances.
    (v) Reportable range of test results for the test system.
    (vi) Reference intervals (normal values).
    (vii) Any other performance characteristic required for test
performance.
    (3) Determination of calibration and control procedures. The
laboratory must determine the test system's calibration procedures and
control procedures based upon the performance specifications verified
or established under paragraph (b)(1) or (b)(2) of this section.
    (c) Documentation. The laboratory must document all activities
specified in this section.

The sentence highlight above “… or introduces a test system not subject to FDA clearance or approval” means that a laboratory should be able to validate a digital pathology solution on their own for clinical use.  And although the FDA has not formally stated whether scanners will be “subject to FDA approval” it seems clear through they will.  The background briefing document about the Advisory Panel Meeting held in October 2009 stated,

FDA hopes to gather information about how to evaluate and compare the performance characteristics of both the light microscope- the reference method- and the digital WSI method-…FDA follows the Code of Federal Regulation 21 CFR 860.7 for ensuring the safety and effectiveness of regulated medical devices…FDA believes the first requirement for adoption of digital whole slide imaging will be the maintenance of the diagnostic accuracy and reproducibility of current surgical pathology diagnostic performance using the conventional light microscope- the current reference method for the diagnosis of cancer and other histopathological entities.

At the Advisory Panel Meeting, Tremel Faison the Scientific Reviewer in the Office of In Vitro Diagnostic Device Evaluation and Safety, stated:

“…everything here at the FDA starts with an intended use. Intended use shapes how the device will be regulated, in what population and ultimately the study design.  For the scope of this Panel meeting, the intended use is defined as the use of whole slide imaging for primary diagnosis of surgical pathology microscope slides in lieu of a microscope. This is not an adjunctive intended use, and for our purposes, we will be considering the use of whole slide imaging for all surgical pathology specimens. It will not be organ or disease specific…

We recognize that the technological advances associated with whole slide imaging make its use a reality. Whole slide imaging systems are not Class I exempt and are therefore subject to premarket requirements.

As I said above, although the FDA has not formally stated whether scanners will be subject to FDA approval it seems clear they will.  So, now what? You could try and go through CLIA for approval of your scanner within the lab or wait for direction from the FDA.  Neither seems like that great of an option.

I started this post with the second most popular question asked of me and here is my response:

What does it matter!  Are you even ready for primary diagnosis with digital pathology?

There are a TON of other areas that need to be addressed to make primary diagnosis with digital pathology work.  Barcodes, laboratory workflow (before and after the scanner), data storage and management, and integration with your LIS, PACS, and EMR.   Just to name a few.

If you are serious about our digital pathology future then stop worrying about what the FDA is saying (or not saying) and get to work! Prepare the labs for change  and start using digital pathology for all those applications you are sick of hearing about.