Growth is all relative. Sales at Myriad Genetics (NASDAQ:MYGN) increased 40% in its recently completed second half of its fiscal year. But that was a slowdown from the 55% increase in the first half. Investors seem content with that; shares are up about 18% today.

Like everyone else, Myriad Genetics is blaming the slowdown on the recession. Its genetic tests for cancer patients haven't experienced much of a slowdown -- the gross domestic product has very little bearing on whether patients get cancer. But about 30% of Myriad Genetics' business comes from ob/gyns, who have experienced a decrease in activity as patients cut out nonessential costs. According to one study, 14% of women have postponed their annual checkup.

Myriad Genetics has hired more sales reps and launched direct-to-consumer advertisements to get patients talking to their doctors about the tests. We should know in a few quarters whether it worked, but management did say it was comfortable with analysts' consensus of $390 million in revenue for the new fiscal year, a 19% increase over the recently completed fiscal year. That's a deceleration from this year, but it's still pretty impressive.

After spinning off its drug business, Myriad Pharmaceuticals (NASDAQ:MYRX), at the end of June, Myriad Genetics is a much more focused company concentrating on diagnostics. The lack of diversity makes Myriad Genetics a little more risky, but it gives investors potential for outsized returns compared with companies that dabble in diagnostics,  like Genzyme (NASDAQ:GENZ), Life Technologies (NASDAQ:LIFE), or QIAGEN (NASDAQ:QGEN).

That growth could be relatively large, considering the potential for genetic testing as more discoveries are found. Just yesterday, in fact, a study was published about a genetic variation that predicts the response to Bristol-Myers Squibb (NYSE:BMY) and sanofi-aventis' (NYSE:SNY) Plavix. Stuff like that is only bound to help a company like Myriad Genetics.

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