Shares in WellCare Health Plans surged nearly 12 percent Friday after the Tampa company blew past analysts' estimates in reporting that its first-quarter earnings quadrupled. WellCare, which provides managed-care services for government-sponsored plans, said it earned $21.3 million, or 50 cents a share, in the quarter ended March 31, up from $6.4 million, or 15 cents a share, a year ago. Its adjusted net income was 66 cents a share, about three times what analysts were expecting. Revenue rose 8 percent to $1.47 billion, up from $1.36 billion a year ago. WellCare also ratcheted up its forecast for the full year, predicting earnings of $3.35 to $3.65 per share, up from a prior forecast of $2.45 to $2.70 per share. The strong performance was tethered to a huge membership gain in WellCare's Medicare prescription drug plans compared to a year ago as the company recovered from sanctions previously imposed by the federal government. Wellcare's stock closed at $47.93 a share Friday, up $4.89.