Updated from 8:13 a.m.

Aetna ( AET) shares jumped Friday after the company boosted first-quarter and full-year earnings guidance well above analysts' consensus expectations.

The Hartford, Conn.-based health insurer said it expects first-quarter 2004 operating earnings of $1.68 to $1.73 a share, excluding any prior-period reserve development. The consensus forecast is $1.54, according to Thomson One Analytics. Aetna's previous EPS forecast was $1.50 to $1.55.

For 2004, the company expects to earn $6.60 to $6.75 a share, excluding items. That's up from its previous forecast of $6.25 to $6.35 and easily exceeds the consensus expectation for $6.41 a share.

Recently shares were up $4.18, or 5.2%, to $83.83, a new 52-week high.

"This early, positive look at our first-quarter financial performance is further evidence of Aetna's growing success in the marketplace," the company said in a statement. "Key contributors to the improved outlook are favorable trends in medical and pharmacy membership, moderate medical costs on both commercial and Medicare business and operating expense efficiency resulting from the higher membership."

Aetna earned 86 cents a share in the first quarter of last year and $5.07 a share for all of 2003.

The company earned $249.5 million, or $1.56 a share, in the fourth quarter of 2003, easily beating expectations, and surpassing earnings of $98.2 million, or 63 cents a share in the year-ago period.

Aetna will announce first-quarter results on April 29.