Quest Diagnostics reported financial results for the second quarter of 2007. Revenue grew 3.7% to $1.6 billion compared to the prior year, with acquisitions contributing approximately 6.5% of growth. Operating margin improved to 16.6% of revenues compared to 13.8% in the previous quarter, due to cost reduction efforts and higher revenue per test. The company expects margins to continue improving for the rest of the year as cost savings are realized and new contracts with health plans generate additional business.