207 - What 99.999% Reliability Really Means

In this episode, Subhi Saadeh sits down with Alan Stevens, CAPT, to break down the concept of five nines (99.999% reliability) in medical devices. They cover where the standard came from, why FDA introduced it in their 2020 draft guidance, and what it means for life-saving products like epinephrine and naloxone injectors.

Alan explains how manufacturers can demonstrate reliability through fault tree analysis, robust process controls, and challenge testing—without needing impossible sample sizes.

If you work in pharma, medtech, or quality, this episode will help you understand what “five nines” really means and how to meet FDA expectations while ensuring patient safety.

Chapters

00:00 – What is Five Nines Reliability?

Intro to 99.999% and why it matters for medical devices.

00:33 – FDA Guidance & Common Misconceptions

2020 draft guidance, sample size myths, and industry confusion.

01:17 – How to Demonstrate Reliability

Feasibility, practical approaches, and FDA expectations.

02:31 – High-Stakes Use Cases

Epinephrine, naloxone, glucagon injectors.

04:00 – Fault Tree Analysis Explained

Breaking down failures and linking to design/manufacturing.

05:25 – Why FDA Chose Five Nines

Balancing feasibility, safety, and ISO 14971 influences.

09:02 – Verification vs. Reliability

Design verification testing vs. true reliability demonstration.

23:16 – Key Takeaways for Industry

Closing thoughts on meeting and maintaining reliability standards.

Alan Stevens CAPT is the Global Head of Complex Devices and Drug Delivery Systems at AbbVie within the RA Emerging Technologies, Devices and Combination Products team. Prior to joining AbbVie, Alan spent 20 years at the FDA/CDRH leading premarket review and policy development for drug delivery devices and combination products.

Subhi Saadeh is a Quality Professional and host of Let's Combinate. With a background in Quality, Manufacturing Operations and R&D he's worked in Large Medical Device/Pharma organizations to support the development and launch of Hardware Devices, Disposable Devices, and Combination Products for Vaccines, Generics, and Biologics. Subhi serves currently as the International Committee Chair for the Combination Products Coalition(CPC) and as a member of ASTM Committee E55 and also served as a committee member on AAMI's Combination Products Committee.For questions, inquiries or suggestions please reach out at letscombinate.com or on the show's LinkedIn Page.