How much is completing a clinical trial worth? Apparently about $140 million. That's how much Sequenom (Nasdaq: SQNM) has increased in value over the last two days after announcing that it completed testing of samples in the study validating its SensiGene Trisomy 21 laboratory developed test.

Note that the only announcement was that the study was completed. There were no results announced for the blood test to determine whether a fetus has Down's syndrome. We don't know that the trial was a success, only that the samples have all been tested -- but that's apparently worth a 20% bump in stock price. Yikes!

Sequenom also released first quarter earnings, but I have a hard time seeing the $2.9 million year-over-year increase in revenue as the catalyst to drive the stock so high. Sure that was a 27% increase, but Sequenom is an $800 million company. The current offerings that bring in a paltry $13.5 million per quarter aren't driving the value of the company: It's the potential sales of the Down's syndrome test that supports the valuation.

The trial was completed earlier than management's guidance of the end of the second quarter, but I have a hard time seeing an extra couple of months worth so much. The company will let principle investigators of the study release the results in a peer-reviewed journal. Considering the history of the company -- including employees accused of fabricating data -- that's certainly the prudent thing to do.

Sequenom's stock has battled back, but I wonder if investors might be getting a little too excited. Think Elan (NYSE: ELN) after Tysabri was put back on the market, only to see another crash when Elan and marketing partner Biogen Idec (Nasdaq: BIIB) reported new cases of the potentially deadly brain infection progressive multifocal leukoencephalopathy.

There are no guarantees that the sensitivity and specificity of the Down's syndrome test will be high enough to justify its use instead of the more-dangerous-but-very-accurate amniocentesis. Investors should tread carefully here.

Interested in keeping track of Sequenom as it launches it develops its Down's syndrome test? Click here to add it to My Watchlist, which will help you keep track of all our Foolish analysis on Sequenom.

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