Shares of OraSure Technologies ( OSUR) jumped after the company said it signed an agreement with Schering-Plough ( SGP) to develop a rapid hepatitis C test.

Under the agreement, Schering-Plough will reimburse OraSure for a portion of the development costs and will provide support in promoting the devices to doctors' offices in the U.S. Shares gained 7% to $8.72.

ImClone's ( IMCL) shares were up 7.9% to $29.18 on an upgrade by Merrill Lynch Thursday.

"We believe there may be a short-term trading opportunity in IMCL due to potentially excessive negative sentiment around near-term Erbitux sales and the potential for positive phase III data from the front-line colorectal or pancreatic cancer study, which we do not believe is reflected into the stock," wrote biotechnology analyst Eric Ende in a research report Thursday.

However, the analyst says he remains concerned about the cancer drug's long-term sales potential considering competition from Amgen's ( AMGN) colorectal cancer treatment Vectibix. Ende upgraded the stock to neutral from sell. Phase III is the stage of trials conducted just before a drug is submitted for Food and Drug Administration review.

Amgen's shares were boosted 2.8% to $70.33 after the stock was upgraded by Bear Stearns analyst Mark Schoenebaum. The upgrade comes despite possible competition this year by Roche's anemia drug Cera.

Shares of Immucor ( BLUD) gained ground Thursday after the company revised its full-year guidance higher on an expected increase in sales.

In its earnings report after the close of trading Wednesday, the company said it expects to report revenue of between $214 million and $218 million, compared with its previous guidance of $204 million to $212 million for its full fiscal year ending in May. Immucor reported earnings of 20 cents a share, compared with 18 cents expected by analysts in its most recent quarter. Shares were up 6.1% to $31.95 Thursday.

Among other health care winners were AstraZeneca ( AZN), gaining 2.8% to $55.39; GlaxoSmithKline ( GSK), 1.7% higher to $54.71; Genentech ( DNA), up 1.3% to $82.88; Gilead Sciences ( GILD), rising 1.5% to $64.09; and Abbott Laboratories ( ABT), gaining 2.4% to $50.12.

Among the losers were Novo Nordisk ( NVO), down 1.7% to $82.01; Hana Biosciences ( HNAB), sinking 6.6% to $5.55; Caraco Pharmaceutical Laboratories ( CPD), off 2.4% to $12.85; Cytori Therapeutics ( CYTX), falling 4.1% to $6.14; and Bentley Pharmaceuticals ( BNT), down 6.8% to $9.49.