Glenn A. Eisenberg
Executive Vice President and Chief Financial Officer at Laboratory Co. of America
Thank you, Adam. Going to start my comments with a review of our fourth quarter results, followed by a discussion of our performance in each segment, and conclude with our 2024 full-year guidance. For reference, we've also included additional business information that can be found in our supplemental deck on our Investor Relations website. Revenue for the quarter was $3 billion, an increase of 3.5% compared to last year, primarily due to organic base business growth and the impact from acquisitions, partially offset by lower COVID testing. The base business grew 7.4% compared to the base business last year, while COVID testing revenue was down 73%. Organically, in constant currency, the base business grew 5.2%.
Operating loss for the quarter was $123 million due to an impairment charge of $334 million related to our Early Development Research Laboratories business as we've experienced soft biotech markets. In addition, we had $125 million of special charges related to acquisitions, COVID and the spin of Fortrea. Excluding these items and amortization, adjusted operating income in the quarter was $395 million, or 13% of revenue, compared to $413 million, or 14.1% last year. The decrease in adjusted operating income and margin was due to lower COVID testing. Base business margins were in line with last year as the benefit of demand and LaunchPad savings were offset by higher personnel and stranded costs and the mixed impact of recently completed hospital partnerships.
Our LaunchPad and stranded cost reduction initiatives delivered around $125 million of savings this year, consistent with our long-term target of $100 million to $125 million per year. The adjusted tax rate for the quarter was 19.5% compared to 25.4% last year. The lower adjusted tax rate was primarily due to the geographic mix of earnings and the benefit from increased R&D tax credits. We expect our adjusted tax rate for 2024 to be approximately 23%. Fully diluted EPS for the quarter was a loss of $1.95 due to the Early Development impairment charge. Adjusted EPS were $3.30 in the quarter, up 8% from last year. Operating cash flow from continuing operations was $580 million in the quarter compared to $607 million a year ago. The reduction in cash flow was due to lower COVID testing.
Capital expenditures totaled $165 million in the quarter. For the full year, capital expenditures were 3.7% of revenue, and we expect this to be approximately 3.5% in 2024. Free cash flow from continuing operations for the quarter was $414 million. The company invested $155 million in acquisitions and paid out $61 million in dividends. While we did not use any cash for share repurchases during the quarter, we completed the accelerated share repurchase program, which reduced our share count by approximately 1.1 million shares in the quarter. At the end of the year, we had $530 million of share repurchase authorization remaining.
For the full year, free cash flow from continuing operations, excluding spin-related cost, was $888 million. The company invested $672 million on acquisitions, paid out $254 million in dividends, repurchased $1 billion of stock, and paid down $300 million of maturing debt. We continue to have a robust pipeline of potential acquisition opportunities that will supplement our organic growth. In addition, we continue to believe that our share repurchase program is an important part of our capital allocation strategy. At year end, we had $537 million in cash with debt of 5.1 billion. Our leverage was 2.5 times gross debt to trailing 12 months adjusted EBITDA.
Now I'll review our segment performance beginning with Diagnostic Laboratories. Revenue for the quarter was $2.3 billion, an increase of 2.6% compared to last year, with organic growth of 0.8% and acquisitions contributing 1.8%. The base business grew organically by 5.7% compared to the base business last year, while COVID testing revenue was down 73%. Total volume increased 2.4% compared to last year as organic volume grew 0.3%, which was constrained by lower COVID testing, while acquisition volume contributed 2.1%. Base business volume grew 5.2% compared to the base business last year as organic volume increased 3.1% while acquisitions contributed 2.2%. Price/mix increased 0.2% versus last year due to an organic base business increase that was mostly offset by lower COVID testing. Base business organic price/mix was up 2.6% compared to the base business last year.
Diagnostics adjusted operating income for the quarter was $354 million, or 15.1% of revenue, compared to $387 million, or 16.9% last year. The decrease in adjusted operating income was due to a reduction in COVID testing. Base business operating income was up due to the benefit of higher organic demand, acquisitions, and LaunchPad savings, which were partially offset by higher personnel costs, including healthcare-related costs. The decrease in margin was due to the reduction in COVID testing and the mix impact from recently closed hospital partnerships, which we expect to improve over time.
Now I'll review our segment performance of Biopharma Laboratory Services. Revenue for the quarter was $695 million, an increase of 7.1% compared to last year due to an increase in organic revenue of 4% and foreign currency translation of 3.1%. The 7.1% revenue growth was driven by continued strength in Central Labs, which was up 12% while Early Development was down 2% due to higher-than-normal cancellations. Biopharma adjusted operating income for the quarter was $109 million, or 15.7% of revenue compared to $95 million, or 14.7% last year. Adjusted operating income and margin increased due to organic growth and LaunchPad savings, partially offset by higher personnel and stranded costs. We ended the quarter with a backlog of $8.2 billion, and we expect approximately $2.5 billion of this backlog to convert into revenue over the next 12 months. Book-to-bill for the quarter was 1.26, with the trailing 12 months at 1.04.
Now I'll discuss our 2024 full year guidance, which assumes foreign exchange rates effective as of December 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. We expect enterprise revenue to grow 4.7% to 6.5% compared to 2023. This includes the favorable impact from foreign currency translation of 60 basis points. We expect Diagnostics revenue to be up 3.2% to 4.8% compared to 2023. The impact from lower COVID testing of around $130 million is expected to be offset by the annualization of acquisitions that were completed in 2023. We expect Biopharma revenue to grow 5.5% to 7.5% compared to 2023. This guidance includes the positive impact from foreign currency translation of 220 basis points. We expect Central Labs and Early Development to both grow within this segment guidance range. We expect margins in Diagnostics and Biopharma to be up in 2024 versus 2023, driven by top line growth and LaunchPad savings.
Our guidance range for adjusted EPS is $14.30 to $15.40, with implied growth rate at the midpoint of approximately 10%. While we do not guide to quarterly performance, it's worth noting that first quarter earnings will be below typical quarterly seasonality due to weather disruption in January that we expect will impact earnings by $0.10 to $0.15 in the quarter. Free cash flow is expected to be between $1 billion to $1.15 billion, with an implied growth rate at the midpoint of approximately 21%. In summary, we expect to drive continued profitable growth and strong free cash flow generation that will be used for acquisitions that supplement our organic growth while also returning capital to shareholders through our share repurchase program and dividends.
Operator, we will now take questions.