A Paper Test for Liver Damage

A startup rolls out a cheap, disposable microfluidics test.

Diagnostics for All, a nonprofit startup in Cambridge, MA, has designed a cheap, disposable blood test for liver damage. The device uses a stack of paper the size of a postage stamp for a test of toxicity for drugs to treat HIV and tuberculosis.

Liver colors: Diagnostics for All’s paper test indicates liver damage by changing color when a drop of blood is added. Normal enzyme concentrations turn the dots on the top row blue and yellow. Higher enzyme concentrations, indicators of liver damage, turn the color of the two dots pink, to match the “control” dots in the middle row.

Some antiretroviral therapies and many TB drugs are toxic to the liver. Patients on HIV and TB medication in rich countries are typically monitored every month for liver damage and taken off the treatment if liver damage becomes imminent. “In the U.S., [testing] is routine. It’s expected, it’s standard,” says Nira Pollock, a faculty member at Harvard Medical School and infectious diseases expert at Beth Israel Deaconess Medical Center in Boston.

In the developing world, liver function testing is often either suboptimal or nonexistent, she says. “People don’t get monitored because the current tests are expensive, or hard to obtain, or [the results] take far too long.” Patients who are being treated for HIV or tuberculosis succumb to liver failure brought on by the medication.

Diagnostic for All wants to change that. “The testing needs to be decentralized, done by health workers going around [to remote parts of the country], if they’re lucky, on motorcycle,” says Patrick Beattie, product development scientist at DFA. Health-care workers at remote stations would take a photograph of the results using their cell phone and transmit the results to a central hospital for analysis.

The device consists of a few layers of patterned paper, laminated for protection. A droplet of blood from a pricked finger will be placed on a small opening in the lamination. A filter inside will stop the red blood cells, and release the remaining plasma into channels in the paper. Reagents which are sensitive to molecular indicators of liver damage will be picked up along the way, and collect with the plasma on the final layer of paper. A color test will indicate how much of the damage marker is present in the blood sample.

“We’re looking at pennies per device,” says Beattie. Since the raw material for the test is paper, this decreases the cost of production exponentially. Also, it makes use of the properties of paper to cause flow, removing the need for expensive equipment like pumps. The startup is a spin-off from the George Whitesides lab at Harvard University, and holds exclusive license to diagnostic technologies that the lab is tailoring for use in the developing world. The liver function test is the first application of the paper-patterned microfluidics assay that the Whitesides lab developed in 2008.

By the yard: Diagnostics for All hopes to mass-produce its disposable paper test for liver damage on sheets.

Diagnostics for All currently runs on funding from philanthropic organizations and grants from the Gates Foundation. But the company is backed by a shrewd business plan. “Our twist on the nonprofit model is that we actively seek partnerships with for-profit companies in the developed world,” says Beattie. Once its technology is licensed, the company plans to collaborate with for-profit companies to market their technology closer home. “It [will give] us a degree of sustainability and the capability to try new tests without relying on grant funding,” Beattie said.

Once its tests have been established for the developing world, the company plans to begin distributing the liver function test for use in the United States, where it also has a market. “If it was easy to monitor for liver function, it could have some impact even here,” says Pollock.

This summer, Diagnostics for All will collaborate with Pollock at the Beth Israel Medical Center to calibrate and validate the test using a bank of discarded blood and serum samples which have already been analyzed. The paper test’s performance will be compared to standard methods used to detect the liver damage markers. Following the clinical sample tests, the company hopes to work with local organizations in Africa and South Asia to begin field tests within a few months. “We are expecting to be in lab testing using real human blood by this summer, field tests later this year, and full scale commercialization by 2012,” says the company’s CEO, Una Ryan. “Once we’ve shown the efficacy of our tests, we’ll apply for local regulatory approval, based on WHO guidelines.”

Bernhard Weigl, the director at the Center for Point-of-Care Diagnostics for Global Health, is optimistic about the results of clinical tests. “Clearly the liver function test is a critical component of anti-retroviral therapy–we’re excited about the idea,” he says. He hopes to begin collaborations with the team at the company soon to assess the test before it begins field tests.

Diagnostic for All hopes to expand the reach of its paper test to other diagnostics as well. Global health patterns could soon be monitored out using this cheap, disposable new test. “We basically intend to put as many known clinical chemistry tests, and as many known immunoassays onto our platform,” says Ryan, “The sky’s the limit.”

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