Glenn Eisenberg
Executive Vice President and Chief Financial Officer at Laboratory Co. of America
Thank you, Adam. I'm going to start my comments with a review of first quarter results followed by a discussion of our performance in each segment and conclude with an update on our full year guidance. For reference, we have also included additional business information that can be found in our supplemental deck on our Investor Relations website.
Revenue for the quarter was $3.8 billion, a decrease of 3.1% compared to last year due to lower COVID testing and the negative impact from foreign currency. This was partially offset by organic based business growth and the impact from acquisitions. COVID testing revenue was down 84% compared to COVID testing last year, while the Base Business grew 9.8% compared to the Base Business last year. Organically in constant currency, the Base Business grew 9.2%, benefiting from the Ascension lab management agreement, which contributed approximately 4% of the organic growth. As a reminder, the outreach business that we acquired from Ascension is treated as an acquisition while the lab management agreement is treated as organic growth.
Operating income for the quarter was $341 million or 9% of revenue. During the quarter, we had $69 million of amortization and $83 million of restructuring charges and special items, primarily related acquisitions, LaunchPad initiatives, and the proposed spin of Fortrea. Excluding these items, adjusted operating income in the quarter was $494 million or 13.1% of revenue compared to $794 million or 20.4% last year. The decrease in adjusted operating income was due to lower COVID testing demand. The margin decline was also negatively affected by the mixed impact from the Ascension TSA and NHP-related constraints. Excluding these items, margins would have been up slightly as the benefit of demand and LaunchPad savings were partially offset by higher personnel expense, inflationary costs, and increased R&D investments in oncology.
Our LaunchPad initiative continues to be on track to deliver $350 million of savings over the three year period ending 2024. The tax rate for the quarter was 23.2%. The adjusted tax rate for the quarter was 22.9% compared to 23.4% last year. The lower adjusted tax rate was primarily due to the benefit from increased R&D tax credits. We continue to expect our full year adjusted tax rate to be approximately 24%.
Net earnings for the quarter were $213 million or $2.39 per diluted share. Adjusted EPS were $3.82 in the quarter, down 37% from last year due to lower COVID testing earnings as Base Business adjusted EPS was up 10%. Operating cash flow was $121 million in the quarter compared to $356 million a year ago. The decrease in operating cash flow was due to lower COVID testing earnings and spin related costs, partially offset by higher Base Business earnings.
Capital expenditures totaled $94 million down from $117 million last year. For the full year, we continue to expect that capital expenditures will be approximately 3.5% of Base Business revenue. Free cash flow for the quarter was $27 million and the company paid out $64 million in dividends. The first quarter is generally the company's softest quarter for free cash flow. We continue to expect our full year free cash flow to be between $1 billion to $1.2 billion.
Now review our segment performance beginning with diagnostics. Revenue for the quarter was $2.4 billion, a decrease of 2.9% compared to last year, driven by organic revenue being down 4.7%, which was due to COVID testing, partially offset by acquisitions of 2%. COVID testing revenue was down 84% compared to COVID testing last year, while the Base Business grew organically by 17.5% compared to the Base Business last year. The Ascension lab management agreement contributed approximately 7% of the growth, while the impact of weather and revenue days benefited growth by approximately 2%.
Total volume decreased 3.3% compared to last year, as organic volume decreased by 5.6%, partially offset by acquisition volume of 2.3%. The decline in volume was due to COVID testing. Base business volume grew 11% compared to Base Business last year, including the benefit from acquisitions of 2.6% and favorable weather and revenue days of approximately 2%. The strong year-over-year growth rate was also impacted by lower than normal volume in the first quarter of 2022, due to Omicron. Price mix increased 0.4% versus last year as the Base Business improved 6.6% and was partially offset by lower COVID testing of 5.7%, currency of 0.3% and acquisitions of 0.2%. Base business price mix was up 8.8% compared to Base Business last year, benefiting from the Ascension lab management agreement of approximately 7%.
Diagnostics adjusted operating income for the quarter was $442 million or 18.5% of revenue compared to $683 million or 27.8% last year. The decrease in adjusted operating income and margin was due to a reduction in COVID testing, which carried a margin of approximately 50% for the quarter. Going forward, we expect a lower margin for COVID testing, but still above the segment average. Base business margin was up approximately 80 basis points driven by organic growth and LaunchPad savings, partially offset by higher personnel expense and the mix impact from the Ascension TSA.
Now review the performance of drug development. Revenue for the quarter was $1.4 billion, a decrease of 4% compared to last year, primarily due to decreased organic revenue of 2.4% and foreign currency of 1.5%. The decrease in adjusted organic revenue was negatively impacted by approximately 8% due to NHP-related constraints, reduced COVID vaccine and therapeutic work, and the previously mentioned FSP contract loss. The early development business was the most constrained by these items. Excluding these impacts, organic Base Business revenue for the segment grew approximately 6% with early development up 17%, central lab up 6% and clinical development up 3%. Reported first quarter drug development revenues on a compounded annual basis grew 6.9% compared to the first quarter of 2019.
Adjusted operating income for the segment was $124 million or 8.8% of revenue compared to $169 million or 11.6% last year. The decrease in adjusted operating income and margin was due to NHP-related constraints, reduced COVID vaccine and therapeutic work and the FSP contract loss, which negatively impacted margins by approximately 350 basis points. Excluding these items, margins would have increased primarily due to demand and LaunchPad savings being partially offset by higher personnel expense, inflationary costs and a write-off of receivables related to small biotech customers. We ended the quarter with backlog of $16.6 billion, and we expect approximately $4.9 billion of this backlog to convert into revenue over the next 12 months.
Now I'll discuss our updated 2023 full year guidance, which assumes foreign exchange rates effective as of March 31, 2023 for the full year. The enterprise guidance also includes the impact from currently anticipated capital allocation, with free cash flow targeted for acquisitions, share repurchases and dividends. Also our guidance assumes that Fortrea will be part of Labcorp for the full year. Following its spin currently anticipated in the middle of the year, we expect to provide updated guidance. We expect Enterprise revenue to grow 1.5% to 4% compared to 2022. This is an increase at the midpoint from our prior guidance of 25 basis points. This increase reflects the Base Business range increasing to 9.5% to 11%, while COVID testing guidance range has been lowered to minus 80% to 90%.
We continue to perform well in diagnostics and are taking up our full year guidance range. We expect diagnostics revenue to be down 0.5% to up 2% compared to 2022. This is an increase at the midpoint from our prior guidance of 100 basis points, primarily due to stronger Base Business volume. This guidance includes the expectation that the Base Business will now grow 12.5% to 14%, which has approximately 5% growth due to Ascension. We expect Diagnostics Base Business margin to be up in 2023 versus 2022, including the unfavorable mix impact from Ascension.
We expect drug development revenue to grow 3.5% to 5.5% compared to 2022. This is a decrease at the midpoint from our prior guidance of 150 basis points due to slower-than-expected backlog conversion, primarily due to investigator site constraints and lower-than-expected first quarter orders. This guidance includes the positive impact from foreign currency of 60 basis points. At the midpoint of our guidance, the compound annual growth rate compared to 2019 is 6.8%, primarily due to organic growth. We also continue to expect that the drug development margin will increase slightly in 2023 compared to 2022.
Our guidance range for adjusted EPS is $16.25 to $17.75. This is a tightening of the range from our prior guidance, while the midpoint is unchanged. This guidance reflects lower earnings from COVID testing, while Base Business adjusted EPS is expected to increase 15% at the midpoint. Free cash flow guidance is $1 billion to $1.2 billion, unchanged from our prior guidance.
In summary, we expect to drive continued profitable growth in our Base Business, while COVID testing volumes are expected to continue to decline through the year. We expect to continue to use our free cash flow generation for acquisitions that supplement our organic growth, while also returning capital to shareholders through a share repurchase program and dividends.
Operator, we will now take questions.