The latest such service was unveiled in a recent paper from Washington University, with a smartphone app called HemaApp used to screen for anemia.
The service uses the camera built into each smartphone to gauge the concentration of hemoglobin and therefore test for anemia in the user.
Bottom of the Pyramid
The developers believe the service could be particularly invaluable in the developing world, where anemia is both very common and more often than not undiagnosed.
The system has been put through its paces already in a small initial trial of 31 patients, with the app performing as well as the more established (and expensive) Masimo Pronto device that has secured FDA approval.
“In developing countries, community health workers have so much specialized equipment to monitor different conditions that they literally have whole bags full of devices,” the team say. “We are trying to make these screening tools work on one ubiquitous platform—a smartphone.”
The device works by focusing the light from the flash in the camera through the user's finger, with the app then analyzing the color of their blood to estimate the concentration of hemoglobin.
The system has been put through its paces in a range of conditions, including the flash alone, with a LED lighting attachment and with a standard incandescent light bulb.
“New phones are beginning to have more advanced infrared and multi-color LED capabilities,” the team say. “But what we found is that even if your phone doesn’t have all that, you can put your finger near an external light source like a common light bulb and boost the accuracy rates.”
In the trials, the app had a reasonable level of accuracy, with 69% accuracy using the standard flash in the phone, 74% when used with a regular light bulb, and 82% accuracy when used alongside a LED light attached to the phone. The Masimo Pronto device currently provides an accuracy level of 81%.
Lower Barriers to Entry
Suffice to say, the device is not intended to replace standard blood tests, and the team make no attempt to compare HemaApp with these tests. What it can do however is provide a more effective means of screening patients earlier, and thus determine whether further tests are required. With the standard camera alone, it was capable of detecting anemia with an accuracy of 79%.
“Anemia is one of the most common problems affecting adults and children worldwide,” the developers say. “The ability to screen quickly with a smartphone-based test could be a huge improvement to delivering care in limited-resource environments.”
The next step for HemaApp is to undergo a more thorough level of testing both nationally and internationally so that they can gather more data on its accuracy levels. The team believe that when the accuracy improves, it could also be used to test for other blood disorders such as sickle cell disease.
“We’re just starting to scratch the surface here,” they say. “There’s a lot that we want to tackle in using phones for non-invasively screening disease.”
Check out the video below to see HemaApp in action.