Diagnostic Test Reader Performs With Cell Phones

A compact rapid diagnostic test (RDT) -reading device has been developed that works in tandem with standard cell phones.

In poor and remote areas of the globe where conventional medical tools like microscopes and cytometers are unavailable, RDTs are helping to make disease screening quicker and simpler.

A team of scientists at University of California, Los Angeles (UCLA; USA) developed a cost-effective RDT-reader attachment, which clips onto a cell phone, weighs approximately 65 g and includes an inexpensive lens, three LED arrays and two AAA batteries. The platform has the ability to read nearly every type of RDT. An RDT strip is inserted into the attachment, and with the help of cell phone's existing camera unit and a special smart-phone application, the strip is converted into a digital image.

The platform then rapidly reads the digitized RTD image to determine, first, whether the test is valid and, second, whether the results are positive or negative, thus eliminating the potential errors that can occur with a human reader, especially one administering multiple tests of various test types. The color changes in RDTs does not last more than a few hours in the field, therefore the ability to store the digitized image indefinitely provides an added benefit.

After this step, the RDT-reader platform wirelessly transmits the results of the tests to a global server, which processes them, stores them and, using Google Maps, creates maps charting the spread of various diseases and conditions, both geographically and over time, throughout the world. Together, the universal RDT reader and the mapping feature, which have been implemented on all smart-phones, could significantly increase the ability to track emerging epidemics worldwide and aid in epidemic preparedness.

RDTs are generally small strips on which blood or fluid samples are placed. Specific changes in the color of the strip, which usually occur within minutes, indicate the presence of infection. Different tests can be used to detect various diseases, including human immunodeficiency virus (HIV), malaria, tuberculosis, and syphilis. The advantages of RDTs are significant as it allows the ability of minimally trained technicians to test large number of individuals, but they can also present problems.

Aydogan Ozcan, PhD, a professor at UCLA, said, "Conventional RDTs are currently read manually, by eye, which is prone to error, especially if various different types of tests are being used by the health care worker. What we have created is a digital universal reader for all RDTs, without any manual decision-making. This platform would be quite useful for global health professionals, as well as for policymakers, to understand cause–effect relationships at a much larger scale for combating infectious diseases." The study was published online on April 16, 2012, in the journal Lab on a chip.

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