Shares of

NBTY

( NTY) were among the best-performing health-related stocks Friday, soaring 18% after the nutritional supplements company posted first-quarter results that beat Wall Street's forecast.

For the quarter ended Dec. 31, the company earned $22.9 million, or 33 cents a share, on sales of $455.3 million. Results included a charge of $2 million, or 2 cents a share. Analysts polled by Thomson First Call expected earnings of 30 cents a share on sales of $446.3 million. During the year-earlier period, NBTY earned $29.9 million, or 43 cents a share, on sales of $420.3 million. NBTY said a strong financial position allowed it to pay down roughly $51 million in debt during the most recent quarter and an additional $25 million in January. Shares were trading up $3.03 to $19.82.

McKesson

(MCK) - Get Report

rose 4% after the health care services company reported better-than-expected third-quarter earnings and raised its guidance. The company earned $193 million, or 61 cents a share, on sales of $22.6 billion. Analysts expected earnings of 52 cents a share for the December quarter. During the year-ago quarter, the company posted a loss of $667 million, or $2.26 a share, on sales of $20.8 billion. Excluding items, the company earned 49 cents a share during the year-ago quarter.

McKesson now sees fiscal 2006 earnings of $2.41 to $2.46 a share, up from its previous forecast of $2.25 to $2.40 a share. For the fourth quarter, the company expects earnings of 65 cents to 70 cents a share. Analysts project full-year earnings of $2.26 a share and fourth-quarter earnings of 69 cents a share. Shares were up $1.76 to $53.89.

Shares of

Idexx Laboratories

(IDXX) - Get Report

rose 3% after the animal health company reported better-than-expected fourth-quarter earnings and raised its 2006 earnings and sales forecasts. The company earned $20 million, or 60 cents a share, including charges of 5 cents a share. Analysts expected earnings of 61 cents a share before charges. During the year-earlier quarter, the company earned $16.9 million, or 49 cents a share. Idexx reported sales of $167 million, up from $144.3 million a year earlier.

For 2006, Idexx now sees earnings of $2.40 to $2.50 a share, up from its earlier view of $2.36 to $2.48 a share. The company raised its sales forecast to $700 million to $710 million from an earlier projection of $695 million to $705 million. Idexx's earnings forecast includes stock-based compensation costs. Analysts project earnings, excluding stock-based compensation costs, of $2.47 a share and sales of $700 million. Shares were trading at $76.80, up $1.88.

Vascular Solutions

(VASC)

fell 7% after the medical device company posted mixed fourth-quarter results and issued a soft first-quarter sales guidance. The company reported a loss of $407,000, or 3 cents a share, on sales of $8.9 million. Excluding certain items, the company said it would have posted earnings of $93,000, or 1 cent a share. Analysts expected a loss of 1 cent a share, before items, on sales of $9.4 million. During the year-earlier period, the company reported a loss of $573,000, or 4 cents a share, on sales of $6.7 million.

Looking ahead, Vascular Solutions sees first-quarter sales of $9.2 million to $9.4 million, below the $10.2 million that analysts projected. The company said that it expects 2006 sales of at least $41 million to $43 million. Analysts are projecting sales of $44.8 million for the year. Shares were down 55 cents to $7.33.

Shares of

Aetna

(AET)

traded actively after the company announced a 2-for-1 stock split and a $750 million stock buyback plan Friday afternoon. The health insurer said that shareholders of record on Feb. 7 will receive one additional share of stock for each share they hold on that date. The stock split will go into effect on Feb. 17. As for the company's stock repurchase plan, the $750 million buyback is in addition to the $580 million still remaining under a previous plan. Aetna shares recently were up $2.04, or 2%, to $92.96.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, up 94 cents to $25.99;

Boston Scientific

(BSX) - Get Report

, down $1.56 to $21.59;

Amgen

(AMGN) - Get Report

, down 74 cents to $71.16;

Guidant

( GDT), down $1.66 to $73.60;

Bristol-Myers Squibb

(BMY) - Get Report

, up 17 cents to $22.79;

Johnson & Johnson

(JNJ) - Get Report

, down 13 cents to $58.51;

Merck

(MRK) - Get Report

, up 44 cents to $34.39;

Schering-Plough

( SGP), up 19 cents to $19.82; and

Elan

(ELN)

, up 37 cents to $14.49.