San Diego's GenomeDx Biosciences said it has sealed deals with three major insurers to cover the company's Decipher test, which measures a patient's risk of metastatic prostate cancer. Stratose, Three Rivers Provider Network and Fortified Provider Network--all PPOs--agreed to count the company and its test as a participating provider. Combined, the insurers cover more than 62.6 million people, the company said. GenomeDx, which launched in 2008, must still secure CMS coverage for the $4,250 test. Insurance reimbursement is the last major milestone diagnostics companies target when they launch new products. Item