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Smartphones: Remote Point-of-care Diagnostics
Abstract & Commentary
By Brian G. Blackburn, MD, and Michele Barry, MD, FACP
Dr. Blackburn is a Clinical Assistant Professor in the Division of Infectious Diseases and Geographic Medicine at Stanford University School of Medicine; Dr. Barry is the Senior Associate Dean of Global Health at Stanford University School of Medicine
Dr. Barry is a retained consultant for the Ford Foundation and has received research or grant support from Johnson & Johnson Corporate Foundation, the Doris Duke Foundation, and the National Institutes of Health. Dr. Blackburn reports no financial relationship to this field of study.
Synopsis: E-health, including mobile phone diagnostics, is a rapidly growing field, which may revolutionize point-of-care diagnostics for physicians.
Source: Tice AD. Gram stains and smartphones. Clin Infect Dis 2011;52:278-279.
Although undeniably useful, gram stains have become less accessible to physicians in an era when clinicians go to the laboratory infrequently to view specimens and hospital laboratories move off-site. This brief report describes a Honolulu hospital's approach to this problem. With the use of smartphones among physicians now widespread and the advent of low-cost digital cameras and microscopes, images of Gram stains can be uploaded in the laboratory and sent out as email or text message attachments to clinicians. Software applications can allow magnification and manipulation of the image while viewing on the phone. Similar technology is already in use in our institution for viewing radiologic and dermatologic images. Implementing systems that incorporate this type of technology could re-invigorate the use of Gram stains and perhaps bring first-hand visualization of such tools to a generation of physicians that would otherwise rarely see them, possibly improving the appropriate use of antimicrobials as a result.
Smartphones are now in widespread use and have the potential to revolutionize many aspects of health care delivery. While the developed world certainly will benefit, it is perhaps in resource-poor settings where smartphones may have their greatest impact. The use of smartphones to disseminate images of Gram stains more widely among the health care team in this report is an encouraging example of the potential of this emerging technology. But the real action is in point-of-care diagnostics. In the developing world, laboratory technicians often have insufficient training, and equipment for microscopy is either unavailable or not portable; yet, such settings are often well-served by mobile phone networks. Thus, mobile phones with cameras are a natural fit for diagnostic imaging and telemedicine.
One group has built a mobile phone-mounted light microscope and demonstrated its potential for clinical use by successfully imaging blood smears with malaria-infected red blood cells (RBCs) and sickled RBCs.1 They also imaged sputum smears positive for Mycobacterium tuberculosis via fluorescence microscopy with the smartphone-microscope. Resolution was sufficient to detect blood cell and microorganism morphology, and with the tuberculosis samples, the authors were able to use automated image analysis software to quantify the number of mycobacteria.1 Another group reported that microscopic images taken with a mobile phone's built-in camera (by simply opposing the mobile phone camera to the ocular of common optical microscopes, without an adaptor) resulted in images of sufficient quality for many diagnostic purposes. Because these image files were small, they could be sent via text message to distant reference centers for tele-diagnosis. Resolution above 0.8 megapixels resulted in images sufficient for diagnosis.2
Another recent development is smartphone-based lens-free digital microscopy. A lightweight, relatively inexpensive holographic microscope can be attached to the camera unit of a mobile phone, with samples loaded from the side.3 Holographic signatures captured by the phone permit reconstruction of images through digital processing. Although this technology requires images to be uploaded to a computer for processing and then re-downloaded to end-users, obviating the need for a traditional microscope may be beneficial in some settings.
A group in rural Thailand is using smartphones to improve malaria case management.4 After patients are diagnosed with malaria, their information is entered into an electronic database and a schedule for clinical follow-up is generated, which is available on smartphones and usable by local health care workers. Follow-up home visits then are conducted in part with the assistance of mobile phones loaded with a follow-up software application geared toward ascertaining symptoms, treatment compliance, and the like. The program also generated summary statistics of malaria cases, which could be automatically sent to study personnel for real-time epidemiological monitoring. Compared to the paper-based system that was in use during the 4 years preceding implementation of this program, the rates of malaria patients appropriately completing follow-up 1 month after infection using the mobile phone-based platform increased from < 50% to 98%, adherence to anti-malarial drug therapy was 94% for P. falciparum-infected patients, and community health care personnel in these low resource settings were able to efficiently utilize the system to perform their work, even in remote areas. A modified version of this program currently is functioning in seven Thai provinces, a key part of an urgent containment program to halt the spread of multi-drug resistant malaria on the Thai-Cambodian border.4
Another group has pioneered wide-field fluorescent and darkfield imaging on a mobile phone with lightweight and relatively inexpensive optical components that are attached to the existing camera unit of the phone.5 In resource-limited settings, this could provide an important tool for quantification of various mobile assays or chips/microarrays, which require the interpretation of fluorescence, such as CD4 counts or viral load measurements in HIV-infected patients.
Potential applications of smartphone technology extend well beyond even these ideas. Medication bottles with embedded wireless chips can remind patients on-the-spot when to take medications, and can then transmit additional reminders for patients and information about medication use/compliance to their doctors via smartphones. Unpublished data suggest this results in increased medication compliance.6 Even the audio-recording capability of smartphones is being developed in one setting as a means of assisting with diagnostics based on heart sounds. Preliminary results indicate that accurate assessment of some components of the cardiac exam can result from acoustic recordings of heart sounds using only a cellphone and hands-free kit. Heart sound analysis software, which can run on a standard cellphone in real time, can detect S1 heart sounds with a sensitivity of 92%.7
Smartphones are clearly an emerging technology with great potential to aid in the development of diagnostics and other tools useful in global health settings. Even in resource-limited countries, the majority of the population in most settings lives within range of a cell phone tower and has a mobile phone. The range of possible applications seems limited only by the number of ideas which are put to the test. In our institution at Stanford, an innovative program called C-IDEA (the Consortium in Innovation, Design, Evaluation, and Action) aims to accelerate progress in the design of extremely affordable diagnostics, drugs, and devices for global health, and a class on Liberation Technology has student teams designing cell phone applications to impact health. As we watch applications such as Facebook and Twitter interface within the current political arena, we look forward to a similar revolution in cell phone diagnostics for health.