Stamp-sized paper test measures liver damage in blood

For HIV and tuberculosis patients in developing countries, this little piece of paper could help monitor liver toxicity caused by drugs.

Scientists have created a new paper-based device that monitors liver injury using just a drop of blood.

Patients infected with HIV and the tuberculosis bacterium, for example, take daily drug cocktails and should be monitored monthly for drug-related liver damage. But patients in developing countries, however, rarely have access to standard lab tests for liver toxicity.

So a team led by Nira Pollock at Beth Israel Deaconess Medical Center and Jason Rolland from Diagnostics For All designed a low-cost, portable device to monitor liver damage for places that lack resources.

It’s like the litmus paper that determines pH. (Remember from junior high? Turns blue for detergent, red for vinegar.) And since it can be used at the point of care, the speedy test – just 15 minutes! -- can determine whether someone has liver toxicity and requires more care.

  1. With this microfluidic device, you apply a small amount of blood from a finger prick onto a 1-inch square piece of paper.
  2. The activity of 2 enzymes in human blood -- aspartate aminotransferase (AST) and alanine aminotransferase (ALT), important markers for monitoring damage to liver cells -- leads to changes in the levels of dyes embedded in specific zones on the paper (pictured).
  3. The color changes correspond to a concentration range for each of the enzymes. When increasing levels of AST are detected in the blood, for instance, it changes from shades of blue to shades of pink.

They’ve already tested their device on over 200 clinical blood samples. The test is expected to cost “only pennies” to produce, according to a BIDMC release, and is currently undergoing trials in Vietnam.

Up to 33 percent of patients on TB therapy can experience drug-induced livery injury, as can upwards of 13 percent of HIV patients. In addition to drug-related liver toxicity, the test can also be used to measure damage caused by viral hepatitis.

The work was published in Science Translational Medicine.

[Via New Scientist, BIDMC release]

Images: Diagnostics For All

This post was originally published on Smartplanet.com