# 207 - What 99.999% Reliability Really Means

- Show: [Let's Combinate](https://hardwarepodcasts.com/podcast/lets-combinate)
- Published: 2025-09-24
- Length: 23m
- Page: https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means
- Listen: https://podcasters.spotify.com/pod/show/letscombinate/episodes/207---What-99-999-Reliability-Really-Means-e38kc43

## Summary

Alan Stevens, Global Head of Complex Devices at AbbVie and former FDA/CDRH leader, explains the FDA's 2020 draft guidance on 'five nines' (99.999%) reliability for life-saving drug-device combination products like epinephrine and naloxone injectors. He clarifies that this standard does not require testing 300,000 samples, but rather demonstrates reliability through fault tree analysis linking design requirements to manufacturing process controls and challenge testing. Stevens emphasizes that while traditional design verification (DV) remains necessary, manufacturers must use sequential challenge testing and robust process controls to meet the high reliability threshold for products where failure could result in death or serious injury.

## Chapters

- [0:06](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=6) Introduction: Alan Stevens and the 99.999% Reliability Standard
- [0:33](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=33) FDA Guidance & The Sample Size Misconception
- [3:15](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=195) Verification vs. Reliability: Conditional Probability
- [4:52](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=292) High-Stakes Use Cases: Epinephrine and Naloxone
- [5:31](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=331) Why FDA Chose Five Nines: Balancing Feasibility and Safety
- [8:27](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=507) Fault Tree Analysis: Linking Design to Manufacturing
- [12:48](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=768) Challenge Testing and Sequential Conditioning
- [22:56](https://hardwarepodcasts.com/podcast/lets-combinate/2025-09-24-207-what-99-999-reliability-really-means#t=1376) Key Takeaways: Lifecycle Reliability and Post-Market Oversight

## Topics

- [Medical & health devices](https://hardwarepodcasts.com/topic/medical-devices)
- [Quality & yield](https://hardwarepodcasts.com/topic/quality-and-yield)
- [Certification & compliance](https://hardwarepodcasts.com/topic/certification-and-compliance)
- [Mechanical engineering](https://hardwarepodcasts.com/topic/mechanical-engineering)

## Most relevant to

large enterprises

## Mentioned

- AbbVie (company)
- FDA (company)
- epinephrine injectors (product)
- naloxone injectors (product)
- ISO 14971 (other)

## Related episodes from other shows

- [Emergency Use Authorization (EUA) 101: What Medical Device Companies Need to Know](https://hardwarepodcasts.com/podcast/global-medical-device-podcast/2020-04-08-emergency-use-authorization-eua-101-what-medical-device-companies-need-to-know) (Global Medical Device Podcast)
- [The Best of Jon & Mike Through the Years](https://hardwarepodcasts.com/podcast/global-medical-device-podcast/2022-12-29-the-best-of-jon-mike-through-the-years) (Global Medical Device Podcast)
- [Living Documentation and Test Automation with Paul Massey](https://hardwarepodcasts.com/podcast/the-pragmatic-embedded-podcast/2021-07-15-living-documentation-and-test-automation-with-paul-massey) (The Pragmatic Embedded Podcast)
- [Meet a Guru: Ryan Behringer](https://hardwarepodcasts.com/podcast/global-medical-device-podcast/2021-07-14-meet-a-guru-ryan-behringer) (Global Medical Device Podcast)
- [Setting the Record Straight on Usability & Human Factors](https://hardwarepodcasts.com/podcast/global-medical-device-podcast/2021-11-03-setting-the-record-straight-on-usability-human-factors) (Global Medical Device Podcast)

## Citing this page

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