People who strive to be the picture of perfect health may find a helper in the form of their smartphones. Engineers have designed an accessory that uses a smartphone camera to measure cholesterol levels.

David Erickson, PhD, of the Sibley School of Mechanical and Aerospace Engineering at Cornell University in Ithaca, N.Y., and two graduate students published an update of progress on their smartCARD device online Nov. 28 in Lab on a Chip. They envision the smartCARD (Smartphone Cholesterol Application for Rapid Diagnostics) as a convenient alternative to home self-diagnostics for people who monitor their cholesterol.

The smartphone system relies on analytical software and a smartCARD accessory that fits over a mobile phone camera. A user places a drop of blood on a commercially available test strip, which fits into a smartCARD reader. The accessory images the color changes on the strip and the app processes the data to display a cholesterol value on the screen.

The Cornell team determined that it takes 60 seconds for the blood sample to go through reactions that result in color changes, with a 1.8 percent accuracy rate for measuring cholesterol levels. Using various smartphone platforms, they found that their system had a maximum error rate of 5.8 percent, which is similar to one home test kit.

They proposed that customizing strips may reduce error between phone platforms. The smartCARD also had the ability to spot erroneous readings, which they wrote was a feature lacking in home test kits.

The smartCARD system measures total cholesterol and cannot discriminate types. The engineers wrote that future work includes minimizing differences across smartphone platforms and using the system to measure test strips for low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides.