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Diagnostics For All

Published By

Daniel Rieckhoff

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Development, Health, Diagnostics, Third World


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Diagnostic labs, no larger than a fingernail, made of paper

29.09.2011, Age: 2394 days

Instead of using pumps, tubes and glass vessels to run blood, urine and other health tests, those tests can now be done on stamp size paper devices. These can be produced simply by photocopying machines and will eventually cost only a few cents. The new technique will likely revolutionise healthcare and agriculture in developing countries.

Diagnostics For All,  a non-profit enterprise based in Cambridge, Massachusetts, USA, developed this exciting, easy-to-use, low-cost new technique with support from Harvard University and the Bill and Melinda Gates Foundation.

From website:

"Patterned paper is a game-changing technology for delivering low-cost medical care in the developing world. Paper is inexpensive, universally available, and compatible with many biological and chemical assays. To fabricate a diagnostic device, DFA patterns channels and assay zones (or wells) of water-repellant materials into a piece of paper roughly the size of a postage stamp. Biological and chemical assay reagents are then deposited in the wells. When blood, urine, saliva, sweat or other biological samples are applied to the device, the paper wicks the sample through the channels to the assay zones, without external pumps or power. Upon contact, the assay zone quickly changes color and results are then easily read by comparing the color change with a reference scale printed on the device. After use, the device can be easily disposed of by burning. As we develop more advanced diagnostics, DFA’s paper devices can be embedded with electrical circuitry to enable resistive heating, electrochemical assays, or initial processing of assay results."

The Bill and Melinda Gates Foundation and the British government also support a recent project to develop similar cheap and simple agricultural diagnostic tests that support livestock health.

From press release:

"Milk and maize can spoil or be contaminated by toxins. Existing tests to safeguard these foods are expensive and often need skilled labor and specialized equipment to apply them properly. DFA’s tests are easy to use and could be administered by the farmers themselves. The cost per test could be a low as a few pennies.

"The first diagnostic will test for milk spoilage by detecting the presence of bacteria. Most tests currently measure the acidity of milk – a proxy test that isn’t as accurate. Many small farmers contribute their herd’s milk to dairy cooperatives in Africa for pooling and sale to processors. Inaccurate testing means a single farmer’s spoiled contribution can contaminate an entire pool. Low-cost tests from DFA can also help pinpoint which farmer’s milk has gone bad, potentially helping identify cows with bacterial infections.

"A second test to be developed under the grant would determine when cows are pregnant or in heat. Identifying cows that are ready for breeding, or already pregnant, will enable small farmers to better manage their herds. Currently, farmers rely on watching their cows for behavioral changes, or perform a potentially dangerous physical examination of the cow. Both methods are less accurate than DFA’s proposed test, which would measure hormone levels.

"Finally, DFA will develop a test for the presence of aflatoxin, a poisonous substance produced by mold in maize. The mold can develop during growing, harvest or storage of the maize, and eating the grain can lead to hepatitis or potentially liver cancer. Children are particularly vulnerable to aflatoxin, and can become stunted and at greater risk of infectious diseases after exposure. Using diagnostics to ensure their harvests are mold-free will protect people from tainted grain and enable the farmers to get the best price for their grain at market.

"Current tests for aflatoxin cost about $6, a prohibitive price for many farmers. DFA’s test would cost less than 50 cents, and perhaps as little as a few pennies."


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