A recently-developed mobile phone
application could make monitoring conditions such as diabetes, kidney disease,
and urinary tract infections much clearer and easier for both patients and
doctors, and could eventually be used to slow or limit the spread of pandemics
in the developing world. The app, developed by researchers at the University of
Cambridge, accurately measures colour-based, or colorimetric, tests for use in
home, clinical or remote settings, and enables the transmission of medical data
from patients directly to health professionals. Decentralisation of healthcare
through low-cost and highly portable point-of-care diagnostics has the
potential to revolutionise current limitations in patient screening. However,
diagnosis can be hindered by inadequate infrastructure and shortages in skilled
healthcare workers, particularly in the developing world. Overcoming such
challenges by developing accessible diagnostics could reduce the burden of
disease on health care workers. Due to their portability, compact size and ease
of use, colorimetric tests are widely used for medical monitoring, drug testing
and environmental analysis in a range of different settings throughout the
world. The tests, typically in the form of small strips, work by producing colour
change in a solution: the intensity of the colour which is produced determines
the concentration of that solution. Especially when used in a home or remote
setting however, these tests can be difficult to read accurately. False
readings are very common, which can result in erroneous diagnosis or treatment.
Specialised laboratory equipment
such as spectrophotometers or test-specific readers can be used to automate the
readouts with high sensitivity, however these are costly and bulky. The new
app, Colorimetrix, makes accurate reading of colorimetric tests much easier,
using nothing more than a mobile phone. The app uses the phone’s camera and an
algorithm to convert data from colorimetric tests into a numerical
concentration value on the phone’s screen within a few seconds. After testing
urine, saliva or other bodily fluid with a colorimetric test, the user simply
takes a picture of the test with their phone’s camera. The app analyses the
colours of the test, compares them with a pre-recorded calibration, and
displays a numerical result on the phone’s screen. The result can then be
stored, sent to a healthcare professional, or directly analysed by the phone
for diagnosis. The app can be used in home, clinical, or resource-limited
settings, and is available for both Android and iOS operating systems. It has
been shown to accurately report glucose, protein and pH concentrations from
commercially-available urine test strips without requiring any external
hardware, the first time that a mobile phone app has been used in this way in a
laboratory setting. Details were recently published in the journal Sensors and
Actuators B: Chemical. Beyond laboratory applications, the app could also be
used by patients to monitor chronic conditions such as diabetes, or as a public
health tool, by enabling the transmission of medical data to health
professionals in real time.
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