The BCW Index, led by strong gains for two of its components, finished the trading week ended Tuesday up 2.8 percent. Beckman Coulter and Molecular Devices led the way, posting double-digit gains for the week. Beckman, whose shares were upgraded last week by investment bank Bear Stearns to "outperform" from "peer perform," rose 11 percent for the tracking period, while Molecular Devices gained 12.4 percent on no news at all.

Only four of the 16 firms in the Index lost value during the week, led by Qiagen, which dropped 1.9 percent.