Lab-equipment company Thermo Fisher (NYSE:TMO) is a leading contender to buy privately owned...

Lab-equipment company Thermo Fisher (NYSE:TMO) is a leading contender to buy privately owned Swedish allergy testing firm Phadia in a deal that could be worth up to $3B, sources said. A purchase of Phadia could weaken Thermo's interest in Gen-Probe (NASDAQ:GPRO).