Updated from 2:15 p.m. EDT

Shares of eResearch Technology ( ERES) were among the worst-performing health and pharmaceutical stocks Thursday, falling 16.4% after the company posted third-quarter earnings that fell below Wall Street expectations and warned that fourth-quarter earnings and sales would be below expectations as well.

The supplier of technology used by biotech companies earned 13 cents a share during the third quarter on sales of $28 million. Analysts polled by Thomson First Call were expecting earnings of 14 cents a share on sales of $27.3 million. Looking ahead, eResearch forecast a fourth-quarter profit of 11 cents to 15 cents a share on sales of $26 million to $30 million. Analysts had been expecting earnings of 16 cents a share on sales of $31.5 million. Shares traded down $2.23 to $11.36.

Align Technology ( ALGN) fell 33.2% after the company delivered in-line third-quarter earnings results but turned in weaker-than-expected sales results. The maker of teeth-straightening products posted pro forma earnings of 7 cents a share on sales of $45.8 million. Analysts were expecting earnings of 7 cents a share on sales of $47.3 million. A year ago, Align earned 2 cents a share on sales of $34 million. Shares of Align traded down $4.92 to $9.90.

Shares of Apria Healthcare ( AHG) fell 4.3% after the company posted mixed third-quarter financial results and lowered its full-year earnings growth projections. The home health care company earned 60 cents a share during the third quarter on sales of $364.6 million. Analysts were expecting earnings of 59 cents a share on sales of $366.5 million. Looking ahead, Apria said that it believes it will turn in full-year earnings growth of 6% to 8%. Previously, the company said that it would grow earnings by 7% to 9%. Shares traded down $1.25 to $27.90.

Genaissance Pharmaceuticals ( GNSC) fell 12.6% after the company lowered its full-year sales guidance. The pharmaceutical company now expects sales of $20 million to $21 million, down from its previous guidance of $25 million. On a pro forma basis, the company now expects sales of $22 million to $23 million, which is down from previous guidance of $27 million. An analyst following the company had expected sales of $25 million. Genaissance said that its revised guidance is due to a shift in the timing of certain contracts. Shares traded down 35 cents to $2.43.

Other health care volume movers included Pfizer ( PFE), up 14 cents to $28.44; Amgen ( AMGN), down $2.13 to $54.28; StemCells ( STEM), up 30 cents to $2.84; Eli Lilly ( LLY), down $2.46 to $52.64; and Merck ( MRK), down 14 cents to $31.26.

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