Shares of Quest Diagnostics ( DGX) sank 3% Thursday after the lab specialist guided lower for 2007.

The diagnostic test outfit earned $151 million, or 77 cents a share, in the fourth quarter, vs. $149 million, or 73 cents a share, in the year-ago period. Analysts surveyed by Thomson First Call expected Quest to earn 74 cents a share.

Revenue grew 8.5% to $1.55 billion, thanks in part to Quest's acquisition of LabOne in November 2005 and Focus Diagnostics in July of last year. Analysts expected revenue of $1.57 billion.

For 2007, the company expects earnings of between $2.70 and $3 a share on $6 billion to $6.2 billion in revenue. Analysts were expecting earnings of $3.21 a share on sales of $6.4 billion for the year.

Quest's 2007 estimates reflect reductions related to the anticipated impact of contract changes, the company said in a press release Thursday. Last October, huge insurer UnitedHealth ( UNH) dropped Quest in favor of rival LabCorp ( LH), saying LabCorp was cheaper.

Shares fell $1.58 to $49.48.

If you liked this article you might like

Nationwide Egg Recall Expanded

10 Toy Fads That Have Faded

Boomers Feel Recession Burden, Blame

KFC Franchisees Want 'Fried' to Be the Focus

Heavy Weights: More Expensive, Less Effective