Friday, December 23, 2016 Written by Ron Chang, Cepheid Fellow and Doug Dority, Cepheid Fellow

Inside Cepheid Innovation

Architecting Ease of Use

Ron and Doug first met when 12-year-old Ron was walking to a friend’s home one day and saw Doug taking apart a bike. The two have been building things together ever since. In this issue of IMPACT we sit down with Cepheid Fellows Doug Dority and Ron Chang as they discuss how they work together to help deliver unprecedented speed and ease-of-use with Cepheid’s molecular testing technology.


Looking back at their first Cepheid project: Real Time Thermal Cycler.

Ron: Our first project at Cepheid was to create a real-time thermal cycler. We came up with the film Smart Cycler tube. All of Cepheid’s PCR happens in the little diamond on this tube.

Doug: In the original prototypes they were trying to mold the film to the inside of the tube. A little innovation that Ron came up with was pressurization of the tube that causes the film to push out against the heaters.

Ron: The problem we had to overcome from our theoretical models — where a perfectly flat heater plate meshes against a perfectly flat side of a reaction vessel is that this perfection doesn’t exist. So we made the film more like a balloon and pressurized it so it would push up against the plate — that's why the tube works.

Doug: Once we had the capability of completing real-time PCR inside the tube in under half an hour, the next paradox we needed to tackle was the four and a half hours of sample prep a laboratorian needed to complete at a bench before the sample could be processed. Sample prep is the holy grail of molecular diagnostics.

The most elegant designs are the really simple designs. The beauty of our cartridge is that it makes complex technology simple to use.

Ron Chang

Our modules are doing real-time PCR and full sample prep. The modules are the most flexible in the industry, and in the future can do any protocol we can imagine — which nobody else can say. The GeneXpert truly is a platform.

Doug Dority

Ron: The genius that Doug added was wrapping the sample prep into a 3 dimensional sealed cartridge. What stops most medical and high-tech detection schemes from succeeding is that inventors overlook the simple stuff.

Doug:The GeneXpert cartridge design is very simple, but it can do anything you can do on the bench, and much more. Our cartridge is completely sealed so that the dry reagents stay dry. When the user opens the lid, the film gets peeled away, which allows the chambers to vent and fluids to be transferred from one chamber to the next, utilizing reagents on board technology.

To see ron and doug discussing the history and the future of genexpert technology please visit:

For a technical animation of how the GeneXpert cartridge works please visit: