FDA proposal threatens access to critical ID diagnostic tests

Every ID clinician knows the importance of reliable, timely diagnostic testing. Recent action in Washington, D.C., however, may severely limit access to ID diagnostics unless we all speak out in opposition.

Laboratory-developed tests, or LDTs, are diagnostic tests that have been developed and analytically validated by individual clinical laboratories. These tests are typically created and implemented when no (or a limited number of) Food and Drug Administration-approved options exist. Examples of important LDTs for infectious diseases include antiviral resistance testing for HIV, hepatitis C and cytomegalovirus. Other examples include comprehensive MALDI and sequence-based organism identification as well as a significant proportion of antimicrobial susceptibility testing. Many of these tests would be considered the “reference method” or diagnostic “gold standard” in medical microbiology. FDA-cleared tests that are modified by clinical laboratories, for example to validate additional sample types not included in FDA labeling, are also considered LDTs. 

LDTs have been under debate in Washington, D.C., for many years. Congress previously attempted to change the way these tests are regulated, but the legislation failed in part due to concerns raised by ID experts, clinical microbiologists and other key stakeholders. Now FDA has stepped in. FDA’s proposed rule on LDTs was released for public comment in September. This new rule would require clinical laboratories to submit evaluations of LDTs to FDA for review, as is done for commercially marketed tests, with the hope that this will improve the safety of LDTs. However, there is no evidence that the vast majority of LDTs for infectious diseases are harmful to patients.  

For many infectious diseases, LDTs are the only or the most reliable option available to provide timely results. In addition, these tests are often considered the standard of care, with years of clinical experience, peer-reviewed literature and clinical guidelines supporting their safety and efficacy. Recent surveys suggest that the proposed rule will cause many clinical laboratories to stop offering LDTs for infectious diseases because they do not have the resources required to submit their tests to FDA for approval. This loss of testing could lead to missed and/or delayed diagnoses, which may in turn negatively influence outcomes. The most frequently ordered LDTs at my institution are used in the care of immunocompromised patients, and several of these are ID tests (Rychert J. et al. Am J Clin Pathol. 2023; 160: 297-302). It is possible that FDA’s proposed rule would disproportionately affect transplant and cancer care delivered at my hospital. 

What you can do

Assuring patient safety while maintaining continued access to accurate LDTs is critical. FDA needs to hear from as many ID clinicians, institutions and other stakeholders as possible. We do not have complete data on how many LDTs are in use and how they are impacting patient care.

Steps you can take to help 

• Use IDSA’s and HIVMA’s action alert to urge FDA to preserve access to ID testing and delay LDT regulation until more complete data on LDTs are compiled and made publicly available. Share this alert with your colleagues, and urge them to contact FDA as well. You don’t have to be an IDSA member to use this action alert. 
• Talk about this issue with your clinical laboratory director. Together, you can approach your institution’s leadership and/or your institution’s government affairs staff and draft a formal comment on behalf of your institution. The FDA proposal and comment portal are available online.
• Let us know how this proposal would impact LDT use in your practice or at your institution. Share examples and anecdotes with IDSA that the Society can use in its advocacy.

FDA’s proposal has significant potential to adversely affect our ability to take care of patients. Please stand up and be heard today!