Shares of Inverness Medical Innovations (AMEX: [[ticker:IMA]]) took an 8 percent hit today on the news that the Waltham, MA-based diagnostics firm has reached an agreement to buy Marietta, GA’s Matria Healthcare (NASDAQ: [[ticker:MATR]]) for some $1.18 billion in cash, stock, and the assumption of debt. Inverness plans to consolidate Matria, a health-management firm, with Alere and Paradigm—two other firms that it has bought during its recent, seemingly unending shopping spree. Most of Inverness’ purchases have been more modest than this one, but last spring it picked up Biosite for $1.6 billion in a bidding war with Beckman Coulter.