Shares of

Nuvelo

( NUVO) were among the best-performing health-related stocks Thursday, surging 39% after the drug developer announced a collaboration with

Bayer

( BAY).

As part of the deal, Bayer HealthCare will get the commercialization rights to Nuvelo's blood clot dissolver, alfimeprase, outside of the U.S. Nuvelo, meanwhile, will retain the domestic commercialization rights and profits from alfimeprase. Bayer will pay Nuvelo tiered royalties of up to 37.5% of Bayer's overseas sales of the blood-clot treatment.

Nuvelo also will be eligible to receive up to $385 million in milestone payments, composed of a $50 million upfront cash payment, up to $165 million in development milestone payments and $170 million in sales and commercialization milestones during the course of the collaboration. Shares of Nuvelo recently were trading up $3.47 to $12.48.

Gentiva Health Sciences

(GTIV)

jumped 22% after the company agreed to acquire home health care and hospice operator Healthfield Group for $454 million. The transaction consists of $55 million in Gentiva stock and about $399 million in cash. The deal, which is scheduled to close in the first quarter, is expected to be accretive to Gentiva's earnings during fiscal 2006. Healthfield posted sales of about $291 million for the year ended Sept. 30. Shares of Gentiva were trading up $3.12 to $17.56.

Shares of

Vascular Solutions

(VASC)

fell 6% after the medical-device maker said fourth-quarter sales will fall short of expectations. When the company posts full results on Jan. 26, it expects to report sales of $8.85 million. In December, the company forecast sales of $9.2 million to $9.5 million. The company blamed the shortfall on sales delays and underperformance at its German sales subsidiary. Vascular Solutions also said it had difficulty ramping up production of its new Pronto V3 catheter during the quarter, which resulted in backorders throughout the month of December. Analysts surveyed by Thomson First Call expected sales of $9.6 million. Shares were trading down 44 cents to $7.22.

BioReference Laboratories

(BRLI)

slumped 10% after the clinical testing company posted a 15% decline in earnings. The company earned $2.8 million, or 21 cents a share, on sales of $44.3 million. A single analyst polled by Thomson First Call had been expecting earnings of 24 cents a share and sales of $45.2 million. A year earlier, the company reported earnings of $3.3 million, or 25 cents a share, on sales of $37.7 million. BioReference said its profit in the most recent period was hurt by a Medicare reimbursement reduction. Shares were trading down $1.80 to $17.15.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, down 5 cents to $24.50;

Merck

(MRK) - Get Report

, down 33 cents to $32.80;

Johnson & Johnson

(JNJ) - Get Report

, down 29 cents to $62.29;

Elan

(ELN)

, down 1 cent to $14.27;

Schering-Plough

( SGP), down 34 cents to $20.59;

Teva Pharmaceutical Industries

(TEVA) - Get Report

, down 36 cents to $42.86;

Bristol-Myers Squibb

(BMY) - Get Report

, down 1 cent to $22.62;

Amgen

(AMGN) - Get Report

, down 35 cents to $79.63; and

UnitedHealth Group

(UNH) - Get Report

, down 11 cents to $61.77.