Quest Diagnostics ( DGX) posted a second-quarter profit drop but guided in line for the rest of 2006.The Lyndhurst, N.J., medical testing company made $132 million, or 66 cents a share, for the quarter ended June 30, down from the year-ago $149 million, or 72 cents a share. Latest-quarter earnings included 12 cents a share in losses tied to the NID test kit unit whose operations are being discontinued. Excluding those losses, latest-quarter earnings were 78 cents a share, 2 cents ahead of the Thomson Financial analyst consensus estimate. Revenue rose 15% from a year ago to $1.58 billion, matching the Wall Street estimate. The company said the acquisition of LabOne boosted revenue by 10%. Quest guided to 2006 earnings of around $3 a share on 15% revenue growth, matching the Thomson Financial targets.