IVD Classification
In vitro diagnostic (IVD) devices are classified under the same Class I/II/III framework as other medical devices but have their own classification regulations and unique regulatory considerations.
IVD regulatory framework
Most IVDs are classified in:
- 21 CFR Part 862 — Clinical chemistry and toxicology devices
- 21 CFR Part 864 — Hematology and pathology devices
- 21 CFR Part 866 — Immunology and microbiology devices
- 21 CFR Part 868 — Anesthesiology (certain blood gas analyzers)
IVDs intended for point-of-care (POC) or home use may have different classification regulations than the equivalent laboratory instrument.
IVD classes and submission pathways
| IVD type | Typical class | Pathway |
|---|---|---|
| General chemistry reagents, common laboratory instruments | I | Often exempt |
| Immunoassay kits, molecular diagnostic tests | II | 510(k) |
| HIV diagnostic tests, blood typing | III | PMA |
| Home-use glucose meters | II | 510(k) |
| Direct-to-consumer genetic tests | II or III | 510(k) or PMA |
| SARS-CoV-2 tests (during PHE) | II or III | EUA or 510(k) |
Home-use IVDs
IVDs intended for use by lay persons at home are evaluated against additional criteria:
- Instructions must be comprehensible to lay users
- Human factors studies may be required
- Labelling must include appropriate warnings and limitations
- Performance must be validated in the intended use setting (home) by intended users
CLIA and IVD complexity
The Clinical Laboratory Improvement Amendments (CLIA) regulations — separately administered by CMS — categorise IVDs by complexity:
| CLIA category | Description |
|---|---|
| Waived | Simple tests approved by FDA for home/POC use |
| Moderate complexity | Standard laboratory tests |
| High complexity | Complex laboratory tests requiring specialised training |
FDA and CMS coordinate on CLIA categorization as part of the 510(k)/PMA review for IVDs used in CLIA-covered settings, though the two regulatory processes operate independently. Manufacturers seeking CLIA waiver classification must submit a separate CLIA waiver application to FDA.
Laboratory-developed tests (LDTs)
Laboratory-developed tests (LDTs) are in vitro diagnostic tests designed, manufactured, and used within a single laboratory. Historically, FDA exercised enforcement discretion over LDTs. FDA issued a final rule in 2024 phasing in oversight of LDTs over a five-year period — LDTs will progressively be subject to the same registration, listing, and premarket review requirements as commercially manufactured IVDs.
Official resources
- FDA — In Vitro Diagnostics
- 21 CFR Part 862
- FDA — CLIA Waiver by Application
- FDA — LDT Final Rule (2024)
CLIA categorization is separate from FDA classification. A device may be classified as Class I by FDA but require CLIA waiver status to be marketed for home or POC use. FDA approval for waived status allows the test to be performed outside a CLIA-certified laboratory.