Updated from 2:42 p.m. EDT

Shares of

Orchid BioSciences

( ORCH) were among the worst-performing health-related stocks Thursday, falling 15.3% after the company posted first-quarter results that fell below Wall Street expectations.

The provider of identity DNA testing services turned in a loss of $1.7 million, or 7 cents a share, on sales of $14.7 million. Analysts polled by Thomson First Call were expecting a much smaller loss of 1 cent a share on sales of $14.8 million. Looking ahead, Orchid said that it continues to expect 2005 sales of $75 million to $78 million, in line with the $77.1 million that analysts are expecting. The company also expects to post operating income -- excluding items -- during 2005. Analysts are expecting 13 cents a share in earnings. Shares traded down $1.64 to $9.10.

Martek Biosciences

( MATK) fell 45.9% after the nutritional supplements and food ingredients company warned that third-quarter sales would be well below expectations. The warning marks the second straight quarter that Martek has disappointed investors. In March, the company issued second-quarter guidance that, at the time, was significantly below estimates. The latest warning stems from an inventory buildup by large customers looking to protect themselves from supply shortages. Additionally, Martek said it expects unforeseen delays in its customers' international expansion plans, which is due in part to Martek's previous inability to supply customers on a consistent basis.

As a result of the issues confronting the company, it now expects third-quarter sales of $38 million to $42 million. Analysts had been expecting sales of $75.4 million. During the fourth quarter, Martek expects sales of $61 million to $76 million. For the full year, sales are expected to be between $220 million and $240 million. Finally, Martek said that earnings would be materially lower than the current estimate. Analysts are expecting 2005 earnings of $1.13 a share on sales of $285.6 million. Shares traded down $27.59 to $32.49.

Shares of

QLT

(QLTI)

fell 2.7% after the company posted first-quarter earnings and sales that were better than expected. The biopharmaceutical company posted earnings of $15.3 million, or 16 cents a share, on sales of $64 million. Excluding items, the company earned $18.2 million, or 19 cents a share. Analysts were expecting earnings of 16 cents a share on sales of $62 million. QLT also announced a share repurchase plan. Over the next two years, the company said that it plans to buy up to $50 million of its own stock. Shares traded down 29 cents to $10.57.

DJ Orthopedics

( DJO) fell 2.2% despite posting first-quarter results that topped forecasts. The medical device maker earned $6.6 million, or 29 cents a share, on sales of $70.3 million. Analysts were expecting earnings of 28 cents a share on sales of $67.7 million. A year ago the company earned $4 million, or 19 cents a share, on sales of $62.2 million. The most recent period included 65 shipping days vs. 61 shipping days a year ago. In addition to forecasting in-line second-quarter sales, DJ Orthopedics said that it continues to expect 2005 earnings of $1.20 to $1.25 a share on sales that are on target to reach the high end of its guidance of $273 million to $275 million. Analysts are expecting 2005 earnings of $1.25 a share on sales of $274.3 million. Shares traded down 55 cents to $24.95.

Shares of

Palomar Medical Technologies

( PMTI) rose 0.9% after the company posted first-quarter earnings that beat expectations by 2 cents. The developer of light-based systems for cosmetic treatments earned $3.5 million, or 19 cents a share, on sales of $17 million. Analysts were expecting earnings of 17 cents a share on sales of $16.3 million. A year ago the company earned $1.2 million, or 7 cents a share, on sales of $10.8 million. Shares traded up 20 cents to $23.21.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, down 23 cents to $26.69;

Elan

(ELN)

, up 44 cents to $4.69;

Johnson & Johnson

(JNJ) - Get Report

, down 67 cents to $67.66;

Merck

(MRK) - Get Report

, up 30 cents to $33.79;

Amgen

(AMGN) - Get Report

, down 56 cents to $57.35;

Genentech

( DNA), down $1.87 to $70.02;

Gilead Sciences

(GILD) - Get Report

, down 14 cents to $36.74; and

Schering-Plough

( SGP), down 8 cents to $20.47.