At this time I’d like to now hand the call over to Peer.
Thank you, Al. Good morning to all joining us from the United States and good afternoon to all joining from Europe. I’d like to welcome you all into our conference call and the opportunity to discuss our results for the first quarter of 2012. As you saw in our release last night, we are pleased with our start into 2012 and improving demand for our products across all customer classes and regions. And sales were $296 million representing a 13% increase at constant exchange rates.
Adjusted operating income rose 14% to approximately $80 million and adjusted diluted earnings per share rose to $0.23 per share. These results led by double-digit growth in all regions and also contributions from all customer classes were ahead of our targets. What were the reasons? Demand for our product among customers and Pharma Applied Testing and Academia improved better over the first quarter of 2011, a period that was adversely affected by the disasters in Japan as well as unrest in Northern Africa.
We also saw solid gains among our growth drivers in molecular diagnostics. These include companion diagnostics for personalized health care. These areas are contributing more than $75 million in sales across QIAGEN and growing rapidly. We’re also seeing solid growth for our disease profiling tests. Growth in this area is further underpinned by the success of QIAsymphony. HPV sales were flat in the quarter. As we have said, HPV is not expected to be a growth driver in 2012, however, remains a solid foundation for our expansion in molecular diagnostics into the growth driver areas that include personalized health care and profiling.
In terms of the 13% constant exchange sales growth, about 7% percentage points came from the Celestus and Ipsogen acquisitions completed in the third quarter of 2011. The rest of business delivered 6 percentage points, so we’re seeing signs of improvement over 2011. A key driver has been the progress we have been making on our strategic initiatives to drive platform success, to add content, to broaden our geographic presence and to grow efficiently and effectively.