Tuesday, April 19, 2022

Brief Blog: MolDx Publishes Draft LCD on GI Dysplasia

Gastric reflux can causes precancerous changes (dysplasia) in the esophagus, and they're traditionally monitored by endoscopy and biopsy.  As in so many areas of surveillance, molecular tests have been entering the space.  

MolDx has released a draft LCD and article on the topic, with comment to May 14.  See Medicare documents DL39256, DA59015.

MolDX: Molecular Testing for Detection of Upper Gastrointestinal Metaplasia, Dysplasia, and Neoplasia



What It Says

The first sentence doesn't sound promising:

Current molecular diagnostic tests that identify individuals with upper gastrointestinal metaplasia, dysplasia, and neoplasia are non-covered by this contractor.

The LCD provides ten bullet points that must be met for coverage.  For example,

The test demonstrates analytical validity (AV) including an analytical and clinical validation for any given measured analytes, and has demonstrated equivalence or superiority for sensitivity or specificity of detecting dysplasia to other already accepted methods for the same intended use measuring the same or comparable analytes.

Not in these bullet points, but later, they remark that tests will "ideally" (quote unquote) have 95% sensitivity and 95% specificity.

While the LCD states, current molecular tests are non-covered, the Billing Article lists code 81479 (which could refer to any list of unknown unstated tests) and lists code 0114U, methylation analysis for Barretts.

But don't get your hopes up, these codes don't appear to be for "coverage," since the billing article opens with the unpromising statement, "To receive a denial, please submit the following."

Analogy to CMS Colorectal Screening Blood Test NCD

Famously, in 2021, CMS released an NCD for blood tests for colorectal screening, promising to cover them if FDA approved and if 74% sensitive (picking up 3 cancers in 4) and 90% specific (about 1 false positivein 10).  No current tests meet that bar (!), although several probably will within a few years. 

Similarly, MolDx opens by saying no molecular Barrett's tests are covered, yet, but provides performance and publications criteria that would trigger coverage in the future and on a rolling basis.

TissueCypher - Barrett's

Very recently, as I have blogged, CMS declared the Cernostics/Castle Bioscience test "TissueCypher," 0108U, to be an ADLT test (price $2350).   Since it is an ADLT test, by definition it must be "covered," probably by Novitas, since TissueCypher is in Pittsburgh.  However, I couldn't find any coverage info on 0108U at the CMS coverage database.   Code 0108U is not mentioned in the new MolDx LCD or article, which it wouldn't necessarily be, since they don't bill into MolDx.  However, MolDx has written coverage (or non coverage) on non-MolDx tests before, such as the MolDx LCD for 4KScore.


Some features are still cryptic in these LCDs.  For example, at some future point, MolDx might have reviewed 6 Barrett's tests, pass 2, fail 4, all under code 81479.  All you see in the article is a bare reference to "code 81479" and you don't know the reviews, the passes, or the fails.  Technically, that information could be found in the MolDx DEX database, but only if you knew in advance the brand names of the labs and tests, which you don't.

And the LCD doesn't spell out some criteria labs may debate during development.  How many patients are needed to study?   Is a single-center study OK?  Or not?   Do there have two separate studies or is one enough?  What proportion need by age 65?   These are key planning questions and aren't mentioned or alluded to in the LCD evidence criteria, but are something might be gleaned in pre-meetings with MolDx.