Shares of Serologicals ( SERO) were among the worst-performing health-related stocks Friday, falling 12% after the provider of biological products posted lower-than-expected third-quarter sales and cut its 2005 guidance. The company reported third-quarter earnings of $7.7 million, or 20 cents a share, on sales of $67 million. Excluding items, the company would have earned $10.5 million, or 27 cents a share. Analysts polled by Thomson First Call were expecting earnings of 27 cents a share on sales of $72.4 million. A year earlier, Serologicals earned $5.7 million, or 19 cents a share, on sales of $46.3 million. On an adjusted basis, which excludes items, the company would have earned $6.2 million, or 20 cents a share, in the year-ago period. Serologicals cuts its full-year adjusted earnings forecast to 92 cents to 95 cents a share from a prior projection of 95 cents to $1. The company now sees 2005 sales of $265 million to $270 million, down from its earlier projection of $275 million to $285 million. Analysts had projected earnings of 96 cents a share on sales of $280 million. Shares were trading down $2.58 to $19.63. Invitrogen ( IVGN) fell 12% after the company posted third-quarter results that missed expectations by a wide margin and trimmed its full-year guidance. Invitrogen earned $23.9 million, or 42 cents a share, on sales of $289.6 million, for the third quarter. Excluding items, the company would have earned $46.7 million, or 80 cents a share. Analysts expected earnings of 88 cents a share and sales of $307.2 million, A year earlier, the company reported third-quarter adjusted earnings of $43 million, or 76 cents a share, on sales of $256.3 million. In response to its recent third-quarter results, Invitrogen said "continued softness at our BioReliance unit, coupled with the timing of media orders to large biomanufacturing accounts, made the third quarter a difficult period."