Celera Genomics plans to announce today that it has developed a genetic test it says can help predict which patients with hepatitis C will eventually suffer liver scarring and so are in most need of treatment. The test, which looks at variations in seven genes, represents another step toward personalized medicine, in which treatments are tailored to patients. Various companies are selling or developing such tests, for purposes that include detecting cancer early, monitoring heart transplants and choosing which drugs may work best to treat cancer, AIDS and heart disease. In the case of hepatitis C, therapy is expensive and...