# LAO: Enzyme Immunoassay, Methotrexate

- Device class: U; regulation: 21 CFR —; FDA's rule: 510(k) required
- FDA decisions: 10
- 510(k) review time 2021–2025: median 145 days (middle half 134–155)
- Recalls: 1 (0 Class I)
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026; MAUDE to Sep 30, 2026

## Decisions per year (last 10)
- 1978: 1
- 1981: 1
- 1983: 2
- 1989: 1
- 1993: 1
- 2011: 1
- 2017: 1
- 2023: 1
- 2024: 1

## Most-cited predicates
- K111904: Ark Methotrexate Assay, Ark Methotrexate Calibrator, Ark Methotrexate Control, Ark Methotrexate Control (Calibration Ran (2011), cited by 2
- K932615: TDX (R)/TDX (R)FLX (R)Mehtotrexate II (1993), cited by 1

Source page: https://510kreport.com/product-code/LAO
Data by year (CSV): https://510kreport.com/product-code/LAO.csv