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Smartphone testing platform quickly, accurately detects parasites in blood
A microscope designed for use with mobile phones may be able to quickly and accurately detect parasitic worms within blood samples, according to recently published data.
“We previously showed that mobile phones can be used for microscopy, but this is the first device that combines the imaging technology with hardware and software automation to create a complete diagnostic solution,” Daniel A. Fletcher, PhD, of the University of California, Berkeley’s bioengineering department, said in a press release. “The video CellScope provides accurate, fast results that enable health workers to make potentially life-saving treatment decisions in the field.”
The full device is composed of a plastic housing, LED lights, microcontrollers, gears, circuitry and a USB port to connect to a smartphone. Pinprick blood samples placed within the device are positioned and examined by an app. By recording parasitic motion using the smartphone’s camera, the app is able to quantify the severity of infection and produce test results within minutes.
“The availability of a point-of-care test prior to drug treatment is a major advance in the control of these debilitating diseases,” Vincent H. Resh, PhD, of UC Berkeley, said in the release. “The research offering a phone-based app is ingenious, practical and highly needed.”
To measure the effectiveness of the new device, Fletcher and colleagues examined the presence of Loa loa among 33 Cameroonian participants infected with the parasites. Blood samples placed into the device were obtained from finger prick, with a second sample obtained and analyzed by gold standard thick-smear methods for comparison.
“Loa-associated [serious adverse events] have led to the suspension of [ivermectin-based mass drug administration] programs in areas highly endemic for co-incident L. loa infection, representing a major setback for onchocerciasis and [lymphatic filariasis] elimination campaigns,” the researchers wrote. “A new approach for rapid, POC quantification of L. loa [microfilariae] load is needed.”
Three hundred videos were collected from participants. Ten were excluded from analysis automatically by the algorithm, five were manually excluded due to illumination malfunction and one removed due to software failure.
Tests with the mobile phone microscope platform matched thick smear counts with 94% specificity and 100% sensitivity for patients above the examined threshold of 30,000 microfilariae/mL, the researchers wrote. Screening results were received in as little as 2 minutes, which included the time taken to fill a capillary with a participant’s blood sample, load the capillary into the device, shoot video and receive the automated results.
“This research is addressing neglected tropical diseases,” Fletcher said in the release. “It demonstrates what technology can do to help fill a void for populations that are suffering from terrible, but treatable diseases.”
Disclosure: Fletcher is a co-inventor and patent holder of the device, and is a co-founder of a company specializing in mobile phone-based otoscope which was not involved in the study. Please see the full study for a list of all other authors’ relevant financial disclosures.