While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Sequenom (NASDAQ:SQNM) gained about 2% today after Jefferies resumed coverage on the genetic analysis specialist with a buy rating.

So what: Along with the upgrade, analyst Brandon Couillard boosted his price target to $5.00 (from $4.50), representing about 26% worth of upside to yesterday's close. So while contrarian traders might be turned off by Sequenom's year-to-date price strength, Couillard's call could reflect a sense on Wall Street that its growth prospects still aren't fully baked into the valuation.

Now what: Jefferies lifted its 2014 EPS outlook for Sequenom from ($0.75) to ($0.31). "Our revised revenue and EPS forecasts reflect the effects of SQNM's recent divestiture of its Biosciences unit, as well as expectations for a profitability & cash flow inflection in 4Q14," said Couillard. Given Jefferies' solid stock-picking track record -- currently ranked in the top 15% of our CAPS community -- biotech-savvy Fools might want to take a closer look at Sequenom.

Brian Pacampara has no position in any stocks mentioned, and neither does The Motley Fool. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.