Double-digit revenue growth in this market is nothing to sneeze at, and LabCorp (NYSE:LH) definitely delivered yesterday.

Revenue was up more than 11% in the fourth quarter, with most of that increase coming from higher volumes, not increased prices. But the company was able to keep its gross margin essentially the same, so price increases weren't really needed.

LabCorp was able to renew its contract with WellPoint (NYSE:WLP) through the middle of 2013, and it still has the contract with UnitedHealth Group (NYSE:UNH) that it stole from arch-rival Quest Diagnostics (NYSE:DGX) a few years ago. With no other national contracts coming up for renewal this year, there shouldn't be any major revenue surprises.

That isn't to say that the growth is going to be stellar this year. We've still got plenty of people out of work, and therefore uninsured, so revenue is only expected to grow 2% to 4%. Better margins and share repurchases could benefit the bottom line a little more, though. The company is guiding for earnings between $4.75 and $4.95 per share.

That puts it trading at about 13 times forward earnings, which isn't dirt cheap. Still, you've got to remember that diagnostic testing is poised to take off. Not only should volume increase as the economy recovers, but the number of routine tests given to patients is also likely to increase as researchers learn more about why drugs work on some patients and not on others.

For instance the FDA is considering recommending that patients get a genetic test before starting Bristol-Myers Squibb's (NYSE:BMY) and Sanofi-Aventis' (NYSE:SNY) Plavix. With Illumina (NASDAQ:ILMN) getting the cost of sequencing a genome down to less than $10,000, the number of discoveries regarding why certain people respond better to certain drugs should increase dramatically in the coming years.

Don't worry, investors. Double-digit earnings growth will be back.

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WellPoint, UnitedHealth, and Quest Diagnostics are Motley Fool Inside Value selections. UnitedHealth Group, LabCorp, and Illumina are Motley Fool Stock Advisor selections. The Fool owns shares of UnitedHealth. Try any of our Foolish newsletter services free for 30 days.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.