Saving Money with the Foldscope in Digital Pathology

Posted 10th September 2018 by Jane Williams

At the recent Digital Pathology and AI Congress, Rebecca Calder and Daniel Stevens presented their research in the poster entitled: Preliminary Studies in the Use of the Foldscope Paper Microscope for Diagnostic Analysis of Crystals in Urine: Issues in the Analysis of Liquid Samples and Potential Applications in Low Budget/Low Tech Regions of the World. You can view the poster here.

Dr. Zev Leifer, who oversaw the project, describes the rationale.

The hero of this story is the Foldscope. It was developed by Dr. Manu Prakash at Stanford as a cheap microscope made of paper, costing under $1.00, and usable for microscopy by students and in more serious research or diagnostic roles by professionals.

The Foldscope is especially advantageous to those in regions of the world where budget and availability of high-end instrumentation is severely limited. At the New York College of Podiatric Medicine, we obtained a Foldscope from Dr. Prakash. We assembled it, using the “fold on the dotted lines” method, inserted a battery and lens, and produced a microscope. Rebecca and Daniel had prior certification and experience as laboratory technicians, including urinalysis.

The project

We set out to determine if the Foldscope could be used as a low-cost microscope, capable of making the same level of diagnostic capacity as a far more expensive microscope. Along the way, a number of issues developed which may be helpful to share with those who may wish to use this system.

Three goals were defined:

1. Can the Foldscope be used to identify relevant crystals in solution?
2. Does the image obtained with the Foldscope compare favourably with that obtained by a traditional light microscope?
3. What operational issues could be identified that affect the usability of the Foldscope in urinalysis?

Preliminary projects were designed to test this by preparing samples of likely target crystals: uric acid and calcium oxalate. This was preliminary, as real urine samples from real patients required complex IRB approval, rules and regulations. In this study, it was determined that the crystals could, in fact, be visualised with this low budget instrument.

In answer to question one, we discovered that yes, the Foldscope can be used to identify relevant crystals in solution. See Fig. 1A (calcium oxalate) and 2A (uric acid).

In answer to question two, our research showed that yes, the image obtained with the Foldscope compares favourably with that obtained by a traditional light microscope. Compare Fig. 1A (Foldscope) with Fig. 1B (microscope) for calcium oxalate. Compare Fig. 2A (Foldscope) with Fig. 2B (microscope) for uric acid.

Furthermore, several issues emerged, different from using a glass or digitised slide. For example, holding the microscope up to a light source resulted in the liquid sample dripping on the observer’s face! This is not only relevant to “ick” and mess, but also to the possible spread of infectious organisms or exposure to toxic molecules to skin, eyes or mouth.

Methods were developed to keep it flat, with the addition of clamps to hold it and a light source appropriately placed. Successful imaging by iPad or cell phone allows the necessary component of telepathology implicit in its application.

Further development is needed as to methodology and as to validation with patient samples. Determination of the full range of identifiable crystals and cells of diagnostic significance would expand the usefulness of this application. The methodology described here may be used to analyse other liquid samples, e.g. blood, with similar concerns.  Its use in low budget and low tech regions of the world would be greatly advantageous.

To take this just a bit further, I might suggest that there are areas, even in nominally first-world countries, that are isolated, in mountainous or desert regions, where funding for equipment or access to medical care or diagnostic capability is limited. Such devices as the Foldscope, for this application or others, combined with photography/telepathology and even digitisation, may be of great advantage. Low budget is an equal opportunity challenge and an equal opportunity inspiration for solutions.

Zev Leifer, Ph.D. is a Professor of Microbiology and Pathology at the New York College of Podiatric Medicine.

To find out more, join us at the 5th Digital Pathology & AI Congress: Europe. See the agenda here.

See the full reference list here.

Tags: digital pathology