There seems to be a pattern emerging among health and fitness devices that do well on crowdfunding platforms: Break a record with your campaign, then ship your device several months late. Pebble broke Kickstarter's funding record, then took more than a year to ship all its backer devices. Misfit Shine raised $100,000 in less than 10 hours on Indiegogo, then delayed its ship date from spring to summer.

Now Scanadu, makers of the Scanadu Scout home health scanner device that broke Indiegogo's record for most funded project last June, has still not shipped its devices to backers, despite an initial promised date (for early backers) of March 31, 2014. The company is now saying they hope the device will ship this winter, but they are not ready to commit to a date.

"We now certainly have the benefit of hindsight," Scanadu CEO Walter DeBrouwer told MobiHealthNews in an email. "With that hindsight, it is clear we underestimated the level of difficulty in developing a whole new category of medical product. This combination of hardware and software has never been done before, and accuracy is extremely important. We did not budget enough time at the onset for the level of testing, validation and verification that would be needed for this type of medical device, using a combination of hardware and software. In retrospect, we would have made a larger investment of our time and resources earlier in the development process focused on testing. And although we had buffers built in, we should have been less optimistic."

The company has been extremely forthcoming about the nature of the delays on its company blog. Initial test units had a persistent accuracy problem which the temperature sensor, which turned out to be interference from heat generated by another sensor. DeBrouwer says the team had hoped it could be fixed with software alone, but they ultimately had to make small changes to the hardware. In the end, the SpO2 and blood pressure sensors also suffered from light and heat interference problems.

In the blog, the team explained that the density and complexity of the device made it hard to make changes to one sensor without affecting the rest of the sensors.

"If one element in our algorithm gives a wrong input, the whole algorithm ecosystem is affected," they wrote. "Meaning every minute change on hardware or software requires us to redo bench testing (on healthy people) and edge-case testing (on sick people) - which then must be re-calibrated again and again with every change. There is so much going on in this small unit by putting all these sensors so close to each other that some friendly fire is inescapable."

In addition to ongoing design challenges, DeBrouwer admitted that manufacturing has been more complicated than anticipated. The first delay to the shipping, which was fixed relatively quickly, was not a problem with the device at all, but a broken manufacturing tool.

"Making one prototype, one hundred, one thousand, one hundred thousand, on to millions, is a very different business model and it requires very different and very specialized skills than at the rapid prototyping phase," he said. "We needed to mix our genetic core with DNA from professional manufacturers of electronic consumer goods and medical device makers."

For backers close to the Scanadu facility, the company has held "Scanathon" events where backers are invited to test the devices in house and help Scanadu build up the robust data sets needed for the device.

"Every issue we have encountered on this journey is an opportunity to develop a new solution," DeBrouwer told MobiHealthNews. "We needed and still need to collect huge amounts of data to test and calibrate our algorithms every time we continue to refine them. This is a challenge our backers helped us overcome in short periods of time by participating in our Scanathons. In the process it is great to meet our backers in person and listen to their feedback."

The delay has not changed Scanadu's plans to seek FDA clearance after the delivery of the initial units, using feedback data from the backers. In fact, DeBrouwer confirmed that the company is in ongoing conversations with the FDA about the strategy.

"Scanadu has had several interactions with FDA and we have a common understanding of FDA's expectations," he said. "They know what we are doing and we know what they want us to do."

The combined strategy of transparency and inviting backer participation seems to have done a good job of placating Scanadu backers: DeBrouwer says only 103 of the 8,000-plus backers who are awaiting a device have asked for a refund.

"Of course there was disappointment with the delay, but the response from our backers has been very supportive and appreciative that we paused shipments in order to deliver devices of the highest quality," DeBrouwer said. "We are setting out to solve big problems, and create the world’s first tricorder. Scanadu's mission is to make this the last generation to know so little about our health and to put a hospital in the palm of your hand. That dream, and the fact that it is diabolically difficult, is appreciated by our backers who have been along on this journey with us. They understand that this is a high mission. We took the deep cut because it was the right thing to do."