FDA Reclassifies TB Immunity Tests: What Manufacturers Must Know

Regulatory Signal: On March 30, 2026, the FDA published a proposed rule in the Federal Register (Docket No. FDA-2026-N-XXXX; Document No. 2026-06064) to reclassify two categories of Mycobacterium tuberculosis (MTB) diagnostic devices from Class III (Premarket Approval) to Class II (Special Controls with Premarket Notification). If finalized, this change will fundamentally alter the regulatory pathway for manufacturers of these widely used tuberculosis diagnostic tools.

What Is Changing — and Why It Matters

The FDA is proposing to reclassify two distinct device types under 21 CFR Part 866 (Immunology and Microbiology Devices):

• Product Code NCD — Mycobacterium tuberculosis cell-mediated immunity tests (e.g., interferon-gamma release assays, or IGRAs)
• Product Code OJN — Mycobacterium tuberculosis cell-mediated immune response enzyme-linked immunospot (ELISpot) tests

Both product codes are currently postamendments Class III devices, meaning manufacturers must obtain Premarket Approval (PMA) before legally marketing them in the United States — one of the most resource-intensive regulatory pathways available. The FDA's proposed rule would move both product codes to Class II, subject to Special Controls and the 510(k) Premarket Notification pathway.

This is not a subtle administrative shuffle. For manufacturers, it represents a meaningful shift in the cost, timeline, and evidentiary burden required to bring a TB immunity diagnostic to the U.S. market.

The Regulatory Background: Class III to Class II Reclassification

Under the Federal Food, Drug, and Cosmetic Act (FD&C Act), medical devices are classified into three risk-based classes:

The PMA process for Class III devices typically requires clinical data demonstrating reasonable assurance of safety and effectiveness, often taking 3–7 years and costing manufacturers $500,000 to over $1 million before a product reaches market. By contrast, the 510(k) pathway for Class II devices generally requires demonstrating substantial equivalence to a legally marketed predicate device — a significantly faster and less expensive process.

According to FDA data, the average 510(k) review time is approximately 177 days, compared to PMA reviews that routinely exceed 400–800 days. For manufacturers of MTB diagnostic devices, this reclassification — if finalized — removes a substantial barrier to market entry.

What Are MTB Cell-Mediated Immunity Tests?

Tuberculosis remains one of the world's most significant infectious disease burdens. According to the World Health Organization (WHO), tuberculosis caused an estimated 1.25 million deaths globally in 2023, making it one of the leading infectious disease killers worldwide. Accurate, accessible diagnostic tools are central to TB control efforts.

Mycobacterium tuberculosis cell-mediated immunity tests work by measuring the immune system's T-cell response to MTB-specific antigens. The two most widely recognized platforms are:

• Interferon-Gamma Release Assays (IGRAs): Whole-blood tests that measure interferon-gamma (IFN-γ) release from sensitized T-cells when exposed to MTB antigens (ESAT-6, CFP-10). Examples include the QuantiFERON-TB Gold Plus and T-SPOT.TB tests.
• ELISpot Tests (Product Code OJN): A more granular variation that enumerates individual T-cells secreting IFN-γ using enzyme-linked immunospot technology.

Both test types are intended as aids in the diagnosis of Mycobacterium tuberculosis infection — they do not diagnose active TB disease on their own but inform clinical judgment in conjunction with patient history, radiology, and microbiological findings.

FDA's Rationale: Why Reclassify Now?

The FDA's proposed rule reflects a deliberate scientific and policy assessment. Under 21 CFR 860.130, the FDA may initiate reclassification when sufficient scientific information demonstrates that general controls and special controls together provide reasonable assurance of safety and effectiveness, eliminating the need for PMA-level review.

For MTB cell-mediated immunity tests, the FDA's rationale includes:

1. Established clinical performance data. IGRAs and ELISpot tests have been in commercial use for over two decades. The clinical evidence base is mature and well-characterized.
2. Defined special controls. The FDA has identified specific performance benchmarks, labeling requirements, and post-market surveillance measures that, when combined with general controls under 21 CFR Part 820, adequately mitigate residual risks.
3. Technological maturity. The underlying immunoassay platforms are well understood; variability risks are addressable through standardized validation protocols rather than full PMA-level review.

Citation Hook: "FDA's proposed reclassification of MTB cell-mediated immunity tests reflects the agency's formal determination that special controls — rather than premarket approval — are sufficient to provide reasonable assurance of safety and effectiveness for these diagnostic devices, as authorized under Section 513(e) of the FD&C Act."

Proposed Special Controls: What Manufacturers Will Need to Demonstrate

The shift to Class II does not mean reduced rigor — it means differently structured rigor. Special controls for these reclassified devices are expected to address:

Performance Testing Requirements

• Analytical sensitivity and specificity benchmarks
• Reproducibility and precision studies
• Interference testing (e.g., hemolyzed or lipemic specimens)
• Comparator testing against established reference methods or predicate devices

Labeling Requirements

• Clear intended use statement specifying use as a diagnostic aid (not standalone diagnosis)
• Specification of patient populations in which the test has been validated (e.g., immunocompromised patients, pediatric populations)
• Disclosure of limitations, including cross-reactivity with non-tuberculosis mycobacteria (NTM) where applicable

Post-Market Surveillance

• Complaint handling consistent with 21 CFR Part 820 (or the forthcoming Quality System Regulation updates under 21 CFR Part 820/ISO 13485-aligned framework)
• Medical Device Reporting (MDR) obligations under 21 CFR Part 803

Effective Dates and Compliance Deadlines

As of the publication date of this article, the FDA's reclassification is at the proposed rule stage. Here is the anticipated regulatory timeline:

Action Required Now: Manufacturers with active PMAs for NCD or OJN product code devices, or those currently pursuing PMA, should submit comments during the public comment period if they have data or perspectives relevant to the proposed special controls framework. The comment window (~90 days) is your primary opportunity to shape the final rule.

Practical Compliance Guidance for Manufacturers

Whether you hold an existing PMA, are in the middle of a PMA submission, or are developing a new MTB diagnostic, here is how to position your organization for this regulatory shift.

1. Audit Your Current Technical File Against Proposed Special Controls

Begin mapping your existing PMA technical documentation against the proposed special controls. Much of the data you already have — analytical validation, clinical studies, labeling — will likely transfer to a 510(k) format, but gaps may exist around predicate selection and substantial equivalence argumentation.

2. Identify Your Predicate Strategy Early

Once reclassification is final, new entrants and current PMA holders seeking to convert will need to identify a legally marketed predicate device. For NCD and OJN device types, established IGRAs like QuantiFERON-TB Gold Plus or T-SPOT.TB — if cleared via 510(k) at that time — could serve as predicates. Work with your regulatory affairs team to map predicate options now.

3. Evaluate Your Quality Management System for 510(k) Readiness

The 510(k) pathway places different documentation demands than PMA. Your Design History File (DHF), risk management documentation under ISO 14971, and design validation records must be organized to support a 510(k) submission. If your QMS was built primarily around PMA-era documentation practices, a gap assessment is warranted.

For organizations that hold or are pursuing ISO 13485 certification, this reclassification underscores the importance of a robust, audit-ready QMS. Learn how ISO 13485 certification supports regulatory submissions across device classes.

4. Monitor the Federal Register for the Final Rule

The proposed rule is not yet binding. Do not abandon PMA activities prematurely. Maintain your current regulatory posture until the final rule is published and effective. Subscribe to FDA docket notifications for Document No. 2026-06064 to receive automatic updates.

5. Prepare for Potential Transition Provisions

Final rules for reclassifications typically include transition provisions for existing PMA holders. These may allow PMA holders to continue marketing under their existing approvals for a defined period while submitting a 510(k) for clearance. Understanding these provisions in advance will help you plan resource allocation and avoid lapses in marketing authorization.

What This Means for the Competitive Landscape

Citation Hook: "Reclassification of MTB cell-mediated immunity tests from Class III to Class II is expected to lower barriers to market entry, potentially increasing the number of manufacturers seeking FDA clearance for tuberculosis diagnostic devices in the United States."

Currently, the PMA burden has limited market participation to well-capitalized diagnostics companies. With a 510(k) pathway, smaller innovators and international manufacturers may find the U.S. market more accessible — increasing competitive pressure on established IGRA platforms. For incumbent manufacturers, this is both an opportunity (reduced regulatory overhead for line extensions and next-generation products) and a competitive threat.

The global in-vitro diagnostics (IVD) market for infectious disease testing was valued at approximately $28.5 billion in 2024 and is projected to grow at a CAGR of 6.8% through 2030, according to industry market research. TB diagnostics represent a meaningful segment of this market, particularly as global health funding for TB elimination programs continues to expand.

The ISO 13485 Connection: Quality Systems in a Reclassified Landscape

Regardless of whether a device is regulated via PMA or 510(k), the FDA's Quality System Regulation (21 CFR Part 820) remains fully applicable. For MTB diagnostic manufacturers, maintaining a conformant quality management system is non-negotiable — and increasingly, FDA expects to see ISO 13485:2016-aligned practices as part of that foundation.

Key ISO 13485 clauses directly relevant to manufacturers of these devices include:

• Clause 7.3 — Design and Development controls (critical for establishing and documenting validation of immunoassay methods)
• Clause 7.5 — Production and service provision (including controls for reagent manufacturing and lot release)
• Clause 8.2.1 — Feedback and complaint handling (essential for MDR obligations post-clearance)
• Clause 8.3 — Control of nonconforming product (particularly important for diagnostic reagents with tight stability windows)

Explore how a compliant ISO 13485 QMS accelerates FDA 510(k) submissions.

My Take: A Long-Overdue Regulatory Modernization

As someone who has guided more than 200 medical device clients through FDA submissions and quality system implementations over the past eight-plus years, I view this reclassification proposal as a pragmatic and long-overdue modernization of the regulatory framework for MTB diagnostics.

The PMA pathway made sense when these test platforms were novel. But IGRA technology has been clinically validated across tens of thousands of patients, in dozens of countries, over more than two decades. The science is settled enough that special controls — with the right performance thresholds — are genuinely sufficient to protect patients.

That said, I would caution manufacturers against treating "Class II" as "low burden." The special controls the FDA is developing for NCD and OJN devices will likely be demanding. Manufacturers who fail to invest in rigorous analytical validation and well-structured 510(k) submissions will face Requests for Additional Information (RAI) that can extend review timelines significantly. The 510(k) pathway rewards preparation, not shortcuts.

Citation Hook: "For Mycobacterium tuberculosis diagnostic manufacturers, the proposed reclassification to Class II represents a strategic regulatory inflection point — one that rewards manufacturers who invest now in robust technical documentation and quality systems aligned with both 21 CFR Part 820 and ISO 13485:2016."

Summary: Key Takeaways for Manufacturers

• The FDA published a proposed rule on March 30, 2026 to reclassify MTB cell-mediated immunity tests (NCD) and ELISpot tests (OJN) from Class III (PMA) to Class II (Special Controls + 510(k)).
• The public comment period is open for approximately 90 days (closing ~June 28, 2026) — submit comments now if you have relevant data.
• Do not abandon active PMA activities until a final rule is published and effective.
• Begin gap-assessing your technical documentation against anticipated special controls.
• Ensure your ISO 13485-aligned QMS is 510(k)-ready, including DHF, risk management, and analytical validation records.
• Monitor FDA Docket No. 2026-06064 for final rule updates.

Last updated: 2026-03-30

Source: FDA Federal Register, Document No. 2026-06064

Jared Clark, JD, MBA, PMP, CMQ-OE, CPGP, CFSQA, RAC is Principal Consultant at Certify Consulting, where he has guided 200+ medical device manufacturers through FDA submissions and ISO 13485 certification with a 100% first-time audit pass rate.