Shares of Affymetrix ( AFFX) were among the worst-performing health-related stocks Friday, falling 19% after the company posted second-quarter results that fell short of expectations and warned that third-quarter results would be below forecasts as well.

The biotech company reported earnings of $7.8 million, or 12 cents a share, on total sales of $84.1 million. Analysts polled by Thomson First Call were expecting earnings of 17 cents a share on sales of $88.1 million. A year ago the company earned $7 million, or 11 cents a share, on sales of $79.8 million.

Looking ahead, Affymetrix forecast a third-quarter loss of 6 cents a share on sales of $95 million. The earnings forecast includes charges of $17.5 million, or 27 cents a share, but excludes non-cash amortization of about $1 million, or 2 cents a share. Analysts had been expecting earnings of 29 cents a share on sales of $101.7 million. Shares were trading down $10.83 to $46.16.

Manor Care ( HCR) rose modestly after the company reported second-quarter earnings that beat forecasts. The operator of nursing homes reported earnings of $37.9 million, or 43 cents a share, on sales of $833.8 million. Excluding items, the company would have earned 48 cents a share. Analysts were expecting earnings of 46 cents a share on sales of $828.8 million. A year ago the company earned $40.1 million, or 45 cents a share, on sales of $799.1 million. In addition to earnings, Manor Care said its board has authorized an additional $300 million for stock repurchases. At the end of the second quarter, the company about $44 million remaining under its previously approved buyback plan. Shares were trading up 5 cents to $36.55.

Shares of Beckman Coulter ( BEC) fell 15% after the maker of testing instruments posted second-quarter earnings that fell well below expectations and slashed its 2005 guidance. The company reported earnings of $47.7 million, or 73 cents a share, on sales of $618.8 million. Excluding items, the company would have posted earnings of $51.9 million, or 80 cents a share. Analysts were expecting earnings of 92 cents a share on sales of $641.5 million. A year ago the company earned $58.3 million, or 88 cents a share, on sales of $597.3 million.

Looking ahead, Beckman Coulter forecast third-quarter earnings of 45 cents to 60 cents a share on sales of $570 million to $585 million. Analysts had been expecting earnings of 88 cents a share on sales of $631.4 million.

Finally, the company announced plans to cut about 350 jobs and combine its two operating divisions, resulting in charges of up to $60 million. Beckman Coulter expects to record the charges during the second half of 2005. Shares were recently trading down $9.78 to $54.47.

American Pharmaceutical Partners ( APPX) rose 4% after the specialty drug company posted second-quarter results that were better than expected. The company earned $20.4 million, or 28 cents a share, on sales of $124.5 million. Analysts were expecting earnings of 26 cents a share on sales of about $121 million. A year ago the company earned $9.2 million, or 13 cents a share, on sales of $97.7 million.

Looking ahead, American Pharmaceutical Partners said that it now expects 2005 sales growth of 8% to 10% in its core generic injectable business, down from previous guidance that called for growth in the midteens. The company said the change in guidance is due "largely to the timing of our launch of Ceftriaxone and what now appears to be more competitive market conditions for this product." The company continues to expect Abraxane sales of $125 million to $155 million. Shares were trading up $1.56 to $41.80.

Other health-care volume movers included Pfizer ( PFE), down 3 cents to $26.56; Amgen ( AMGN), down $1.78 to $80.17; Millennium Pharmaceuticals ( MLNM), down 43 cents to $10.05; Priority Healthcare ( PHCC), up $1.73 to $27.58; Schering-Plough ( SGP), up 31 cents to $20.42; IMS Health ( RX), down 50 cents to $27.16; UnitedHealth Group ( UNH), up $1.69 to $50.85; Dendreon ( DNDN), down 85 cents to 6.17; Johnson & Johnson ( JNJ), up 13 cents to $64.11; Elan ( ELN), up 1 cent to $7.78; and Merck ( MRK), down 44 cents to $30.94.