Thursday, August 10, 2023

MolDx Proposes Revisions to Transplant Molecular Testing Policy (L38568); Open for Comments

Over the past year, CareDx share price rose and fell with variants in MolDx's billing article for molecular testing for organ transplants.  Other companies in the space have had their own decisions to face.

On August 10, 2023, MolDx offers a new draft LCD for molecular rejection testing.   The LCD number is unchanged (we had LCD DL38568 back in 2020 and now DL38568 for 2023).  The oldest title under this LCD number was "Liquid biopsies for solid organ transplantation."  

EXISTING ACTIVE LCD: Molecular Testing for Solid Organ Allograft Rejection (here

NEW DRAFT PROPOSAL: (same title)  (here)

There will be an open public comment meeting (Palmetto) on September 18, 2023.  The comment period runs August 10 to September 23.   See also coverage at Genomeweb here.

MolDx notes that back in November 2022, it held a two-day, publicly streamed contractor advisor (expert advisor) meeting.

The LCD revision is officially listed as "contractor initiated" but it surely occcurs in the context of numerous complaints, requests for clarifications, and meetings.

These updates are News.  For example, Genomeweb ran an extended premium article on August 8, 2023, (here).  After the revision of a prior MolDx billing article after which CareDx actually withdrew its official revenue guidance.  See an open access article about CareDx Medicare coverage August 9, 2023 (here).  And, CareDx stock this year has traded in a broad range from $7 to $17, sometimes moving abruptly.

Nerd note: As of today, August 10, the LCD has no "associated documents" like new draft billing articles.  These may appear a bit later than the draft LCD itself.  For these LCDs, the billing articles can be very important.


OK, so What's Up?

The MAC says that the LCD is changing, besides its title, only "for clarity" and "only comments pertaining to the changes for clarity" will be considered.

MolDx inserts language about the CAC meetings last November:

Contractor Advisory Committee (CAC) Summary

Kidney and Liver Allograft CAC

On November 16, 2022, Noridian and Palmetto jointly facilitated a CAC to discuss molecular testing for the diagnosis of acute rejection in kidney or liver transplant recipients where GEP, dd cfDNA, and multiomic tests were discussed. The subject matter experts (SMEs) expressed a high degree of certainty that there is sufficient evidence to support the use of molecular tests like dd cfDNA in kidney allograft patients.

Heart and Lung Allograft CAC

On November 17, 2022, Noridian and Palmetto jointly facilitated a CAC to discuss molecular testing for the diagnosis of acute rejection in heart or lung transplant recipients where GEP and dd cfDNA tests were discussed. The SMEs were unanimous that the evidence is sufficient to support the use of GEP and/or dd cfDNA for surveillance of acute organ injury to help replace an unnecessary biopsy. However, they also agreed that there is a lack of data to support the routine use of molecular combination testing. Moreover, they did not endorse the use of molecular diagnostic tests in lieu of biopsy in patients with a very high clinical and laboratory suspicion for acute rejection and who can also safely tolerate a biopsy. All SMEs agreed that these tests do not discern the etiology of organ injury, indicating that they had a high degree of confidence in the detection of allograft injury, but additional clinical testing was necessary to discern the cause.

Substantive Revisions to LCD

There are a number of revisions to the body of the LCD, besides the insertion of the public meeting text I just showed.   I have included a cloud PDF that redlines the current version (R1 July 2023) and the new version (DL38568 August 10 2023).


  • The LCD now opens with "Definitions," But nearly all the so called "Definitions" are actually abbreviations.   "CV = clinical validity," is not a "definition" of clinical validity!, it is an abbreviation.
  • Requiring an affiliation with a transplant center is struck out.
  • Molecular tests are covered after the result of relevant pre-tests are known.
  • Molecular testing "in lieu of" a surveillance tissue biopsy, is covered no more often than the surveillance tissue biopsy would have been covered.
  • Banff classification always updates to "^the most current" one.
  • The text formerly stated, "only one test...unless a second test is reasonable and necessary."  
    • Now it states "only one molecular test" is covered, and "unless a second test (etc)" is struck out.
  • There is some general explanation that patients get both serologic monitoring tests and MAY get surveillance [protocol] biopsies as well.
  • A sentence that split rejection into either cellular- or antibody-mediated is struck out.
  • "Sophisticated methods" become "advanced technology methods."
  • There is a literature discussion comment that conjoint gene expression and cfDNA testing improve management "in certain circumstances"...but this is never defined.   
  • There is a remark that only 18% of transplant centers perform routine, surveillance kidney biopsies, attributed to the advisors meeting in November.
    • It's not clear what is intended by this.  The risk-benefit profile of ddDNA testing and physical CT-guided biopsy are very different, so the decisions and use cases are different.  Amniocentesis as a first test is less common in the NIPT era, for example.  
Is there really no change in coverage?

The new draft belabors that there is "no change in coverage" and only changes for "clarity."  

However, there seem to be some changes in coverage.  For one example, in the prior version, tests could be ordered "by physicians considering the diagnosis of AR affiliated with a transplant center" and now "affiliated with a transplant center" is literally struck out.   That seems more like "a change" than "a clarification."  Another section said, "only one test is covered unless..." and that is changed to "only one test is covered. [period]"


No new citations were added; the 35 citations are the same as the current LCD.   The year distribution is 1991-2020, with the median year of publication being 2017, and no publications cited after 2020.  Assuming the LCD is finalized in 2024, the youngest publication will be 4 years old.

Coverage Rules and Discussion Section Should Be Independent 

Although the only impact on covered care (for clarity) should be changes in the "coverage" section (e.g. the "bottom line" for payment) there are a number of changes to the summary-of-evidence section too.   

Reading numerous LCDs, I usually feel that LCDs should be written for complete clear rules for "coverage" only in the "coverage" section.  This section's functional text should not be dependent on back-and-forth interpretations of verbal nuances (where two readers can easilyi differ) that are found down in the often-rambling "review of evidence" discussion section.  I was recently tasked with reading an LCD, which was not particularly long, on bladder cancer biomarkers (L36678) and found it very confusing what the actual, bottom line, plain-old coverage rules were.  Besides scattering coverage remarks around the LCD like an Easter egg hunt, the labeled "coverage" section was bloated with extraneous remarks unrelated to coverage.    


I ask ChatGPT to assess this blog.