DOW JONES NEWSWIRES 
 

Tenet Healthcare Corp. (THC) boosted its full-year outlook as it said preliminary first-quarter earnings came in well above analysts' estimates.

Shares surged 34% in premarket trading Tuesday to $1.90. Through Monday the stock had lost nearly 80% of its value the past seven months as the hospital operator struggles to gain its footing after settling government probes in 2006 over past pricing plans.

The company has changed management, shed hospitals and made improvements that earned it good-quality ratings from the Department of Health and Human Services. Still, it faces high-supply costs, delays in key asset sales and high debt levels.

Tenet expects first-quarter earnings of 37 cents a share, including a net of 29 cents in gains. Analysts surveyed by Thomson Reuters expected break-even results. However, it expects revenue of $2.28 billion, below analysts' views of $2.32 billion.

The company also boosted its full-year view on earnings before interest, taxes, depreciation and amortization to $760 million to $825 million from $735 million to $800 million.

"Excellent cost control, including a sustained decline in malpractice expense, contributed to a very strong first quarter and the highest operating margin we've reported in six years," Chief Executive Trevor Fetter said.

Tenet saw same-hospital admissions fall 1.3% in the first quarter as same-hospital managed-care admissions declined 3.2%. Same-hospital outpatient visits edged up 0.7%.

-By Kerry E. Grace, Dow Jones Newswires; 201-938-5089; kerry.grace@dowjones.com