Liver damage is a potential side effect of virtually any medication that is metabolized by the liver. The risk of acquiring this damage is even greater in patients that are required to take cocktails of drugs- one prime example being HIV positive patients. These high-risk populations should be closely monitored for liver damage in order to avoid death as a result of liver failure. AIDS patients in Africa, however, are 12 times more likely to die from liver failure than their American counterparts largely due to a lack of proper resources needed for diagnosis. This may soon change.
A new diagnosis test created by a Harvard professor, Dr. Whiteside, has the potential to diagnose liver damage for less than a penny. This device is smaller than a postage stamp and is composed of a sheet of paper, wax, and reagents that are used to measure the level of aspartate aminotransferase (AST) in a patient’s blood. With a single drop of blood placed into the center of the layered paper, the plasma is filtered through a porous membrane allowing it to seep into the second layer. At this stage, the plasma comes in contact with two chemicals. If AST is present in the plasma, it will bind to these two chemicals and sulfite ions will be released. These sulfites trigger a chemical reaction with the blue methyl dye on the last layer of the diagnostic test that turns the dye colorless. Since this layer contains a pink background, the blue dye forms an initial purple spot on the sheet. If, however, the sulfites cause the dye to undergo the chemical reaction, the spot will be light pink by the end, signifying high levels of AST in the blood, which indicate liver damage.
This new form of diagnostic testing can have drastic effects in international health care. The low cost and feasible manufacturing of the exams can potentially lead to an increase in diagnosis a decrease in death attributed to liver failure. Not to mention, antibodies can potentially replace the two chemicals in the second layer in order to diagnose viral infections.
Original Article: http://www.nytimes.com/2011/09/27/health/27paper.html?pagewanted=1&ref=science