Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of medical lab operator Celera (Nasdaq: CRA) soared 30% on Friday after larger rival Quest Diagnostics (NYSE: DGX) said it would acquire the company for about $671 million in cash.

So what: The deal values Celera at $8 per share and represents a 28% premium to its Thursday closing price. Quest Chairman and CEO Surya Mohapatra noted that the move will provide "immediate access to an impressive range of proprietary tests and products, and a strong pipeline of biomarkers for the future."

Now what: The boards of directors for both companies have approved the deal and expect it to close at the end of April. While Quest expects the transaction to add roughly 1% to its top-line growth this year, the deal should also pressure its bottom line slightly in 2011. Of course, with Quest also having just announced the purchase of Athena Diagnostics, which specializes in diagnostic tests for neurological disorders, management seems to be positioning itself nicely for long-term growth.   

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