Lab-testing firm and Motley Fool Stock Advisor pick LabCorp (NYSE:LH) once again outperformed an archrival and continued to fire on all cylinders.

So far this year, Quest Diagnostic's (NYSE:DGX) pain has been LabCorp's gain, as managed care giant UnitedHealth Group (NYSE:UNH) decided to go with the latter lab tester and end a contract with Quest. So while Quest is struggling to maintain positive sales and earnings momentum, LabCorp easily posted double-digit gains in the top line, which it was able to leverage into an adjusted diluted earnings per share gain of 25%.

LabCorp continues to focus on the managed care business, and mentioned: working with existing client Wellpoint (NYSE:WLP); a renewed deal with Cigna (NYSE:CI), which also uses Quest; and an effort to win business with Humana (NYSE:HUM). However, as of July 1, LabCorp's current contract with Aetna (NYSE:AET) ends and will not be renewed.

But the good times are expected to continue, as LabCorp expects full-year revenue growth of 13%-14% and earnings expansion of as much as 30%. Better yet, based off forward company guidance, LabCorp trades at a lower multiple of free cash flow than Quest.

That's because LabCorp is currently growing much faster, a trend that has existed for as long as I can remember. It also posts higher profit margins, even though Quest continues to be the larger firm in terms of overall sales. As it stands currently, Quest is the value play, as it regroups from the UnitedHealth loss, and LabCorp continues to take names as the steady growth player in the industry. Overall, I believe the space continues to be worth tracking and offers opportunities -- regardless of which type of Foolish investor you are.    

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Fool contributor Ryan Fuhrmann is long shares of Quest, but has no financial interest in any other company mentioned. Feel free to email him with feedback or to discuss any companies mentioned further. Quest and UnitedHealth are Inside Value recommendations. The Fool has an ironclad disclosure policy.