Thermo Fisher Scientific Inc., of Waltham, Mass., has made a bold play in the molecular diagnostics market, including infectious disease testing, with its proposed $11.5 billion acquisition of Qiagen NV, of Venlo, Netherlands. Word of the deal comes after reports late last year that named Thermo Fisher as a potential suitor for Qiagen. However, in late December, Qiagen said it had wrapped up a review of potential strategic alternatives and decided its standalone business plan represented the best opportunity for value creation.