Good morning, and welcome to the IDEXX Laboratories third quarter 2021 earnings conference call. As a reminder, today's conference is being recorded. Participating in the call this morning are Jay Mazelsky, President and Chief Executive Officer, Brian McKeon, Chief Financial Officer, and John Ravis, Senior Director, Investor Relations. IDEXX would like to preface the discussion today with a caution regarding forward-looking statements. Listeners are reminded that our discussion during the call will include forward-looking statements that are subject to risks and uncertainties that could cause actual results to differ materially from those discussed today. Additional information regarding these risks and uncertainties is available under the forward-looking statements notice in our press release issued this morning, as well as in our periodic filings with the Securities and Exchange Commission, which can be obtained from the SEC or by visiting the investor relations section of our website, idexx.com.
During this call, we will be discussing certain financial measures not prepared in accordance with generally accepted accounting principles, or GAAP. A reconciliation of these non-GAAP financial measures to the most directly comparable GAAP measures is provided in our earnings release, which may also be found by visiting the investor relations section of our website. In reviewing our third quarter 2021 results, please note all references to growth, organic growth, and comparable growth refer to growth compared to the equivalent period in 2020, unless otherwise noted. During the question- and- answer session, if you have a question, please press star then one on your touch-tone phone. To allow broad participation in the Q&A, we ask that each participant limit their questions to one with one follow-up as necessary.
We appreciate you may have additional questions, so please feel free to get back in the queue, and if time permits, we'll take your additional questions. I would now like to turn it over to Brian McKeon.
Good morning, everyone. We're pleased to share another quarter of excellent financial results for IDEXX, driven by continued strong global momentum in our companion animal business. In terms of highlights, revenue increased 12% as reported and 10% organically compared to high prior year growth levels. Third quarter results reflected 11.5% organic growth in CAG Diagnostic recurring revenues, with double-digit gains across U.S. and international markets. Two-year average annual organic growth for CAG Diagnostic recurring revenue sustained at 16%, reflecting mid- to high-teens two-year average gains across our major modalities. We also achieved a record third quarter level of premium instrument placements with strong global gains across our major platforms.
High revenue growth and sustained operating margins compared to high priority levels supported delivery of $2.03 in earnings per share, an increase of 12% on a comparable basis. Momentum in our CAG business has us on track to deliver 15.5%-16% organic revenue growth, 200-225 basis points in comparable operating margin gains, and 26%-27% comparable EPS growth in 2021 at the higher end of our previous guidance ranges. We'll walk through the details of our updated full-year outlook later in my comments. Let's begin with a review of our third quarter results and recent sector trends. Third quarter organic revenue growth of 10% was driven by 13% CAG revenue gains and 13% growth in our water business.
These gains were moderated by a 23% organic decline in LPD revenues compared to high prior levels, which benefited from the ramping of African swine fever testing in China, as well as by a $3 million year-on-year decline in human COVID PCR testing. CAG Diagnostic recurring revenues increased 11.5% organically compared to strong prior growth levels, reflecting 10% gains in the U.S. and 14% growth in international regions. On a two-year basis, average annual CAG Diagnostic recurring revenue growth was 16% overall, reflecting 16% gains in both U.S. and international regions. Strong CAG results were also supported by 15% organic growth in veterinary software services and diagnostic imaging revenues, in addition to benefits from our recent ezyVet acquisition and 33% year-on-year growth in CAG Diagnostic instrument revenues.
We continue to achieve very high levels of supply chain reliability across our business, reflecting outstanding performance by our operating teams, enabling us to support continued high levels of growth and customer service. Continued strong U.S. CAG Diagnostic recurring revenue growth was supported by year-on-year gains in U.S. clinical visits. U.S. clinical visit growth was 2% overall in Q3, with solid gains across wellness and non-wellness categories. This compared to strong 7% gains in the third quarter of 2020, which included benefits from pent-up clinical demand, including very high growth in wellness testing. On a two-year basis, U.S. same-store clinical visit growth increased at a 4.4% average annual rate, sustaining above annual clinic visit growth trends heading into the pandemic.
The IDEXX U.S. CAG Diagnostic recurring revenue growth premium to U.S. clinical visits was approximately 850 basis points on a one-year basis, compared to very strong prior growth levels for diagnostic testing, which supported a 1,500 basis points growth premium last year. On an average two-year basis, which helps to calibrate for year-on-year pandemic dynamics, the growth premium was approximately 1,200 basis points in the third quarter, slightly higher than the two-year trends in the H1 of the year. Expanding pet healthcare services, including continued solid increases in the utilization of diagnostics, supported a 7% same store increase in overall veterinary clinic revenues in Q3. Diagnostic revenues per practice increased 7% on a one-year basis and 13% on an average two-year basis, consistent with recent two-year growth trends.
IDEXX innovation and commercial engagement continues to build on positive healthcare demand trends, driving high Q3 organic revenue gains across our major testing modalities globally. IDEXX Reference Lab revenues increased 10% organically in Q3, with similar year-on-year gains in U.S. and international regions. Global reference lab gains continue to be driven by high same-store volume growth with strong gains across testing categories. IDEXX VetLab consumable revenues increased 14% organically in the third quarter, reflecting double-digit gains in the U.S. and continued high growth in international regions. Gains continue to be supported by increases in testing utilization across regions, high customer retention levels, and expansion of our global premium instrument install base.
IDEXX achieved a third quarter record of 4,307 premium CAG instrument placements, up over 1,100 units or 36% from constrained prior year levels, reflecting strong gains across U.S. and international regions. We saw strong global placement gains across our platforms, with Catalyst up 22%, premium hematology up 62%, and SediVue up 30%. The quality of CAG instrument placements remains excellent, reflected in 344 Catalyst placements at new and competitive accounts in North America, up 14% year-on-year, and 1,003 new and competitive placements in international regions, up 17%. We also benefited from 571 second Catalyst placements, driven by continued strong demand from high-volume customers. The global rollout of ProCyte One continues to support strong overall placement momentum with the majority of our ProCyte One placements in new and competitive accounts.
New instrument placements and continued very high customer retention levels supported a 14% year-on-year growth in our global premium install base, setting a foundation for continued high growth in IDEXX VetLab recurring diagnostic revenues. Rapid assay revenues expanded 9% organically in Q3 compared to strong prior year demand levels that included benefits from pent-up demand for wellness testing. Growth in vector-borne disease testing drove solid year-on-year volume gains in the U.S., and global growth continues to benefit from double-digit gains in international regions. High CAG diagnostic recurring revenue growth remains primarily volume driven across our modalities with consistent overall net price gains of 2%-3%. In other areas of our CAG business, our veterinary software and diagnostic imaging revenues increased 15% organically, and 33% as reported, including benefits from our recent ezyVet acquisition.
Strong growth in veterinary software services was supported by double-digit comparable gains in PIMS placements and continued strong growth in related recurring services. We also saw continued high growth in diagnostic imaging system placements driven by our entry-level ImageVue DR30 platform with nearly 80% of placements at competitive accounts. We continue to see 20%+ growth in recurring digital service revenues, including expansion of Web PACS subscriptions aligned with our expanding cloud-based capability. Turning to other business segments, water revenue increased 13% organically in Q3 compared to 4% organic declines in last year's third quarter as this business continues to track back towards pre-COVID growth levels. Business growth was supported by solid gains across compliance and non-compliance testing categories. Livestock, Poultry, and Dairy revenue decreased organically 23% in Q3 compared to 18% organic growth levels in Q3 of 2020.
Overall dynamics in our China LPD and related export testing businesses offset growth in other global regions. As expected, Q3 revenue growth was constrained by the lapping of high prior year demand for African swine fever testing and lower herd health screening levels. We're now seeing additional constraints on China LPD testing demand reflecting relaxation of local African swine fever disease management approaches in China, and as we work through impacts from low pork prices and changing government regulations related to livestock infectious disease testing programs. Reflecting these factors, we're planning for continued lower LPD revenues overall in upcoming quarters, which is factored into our 2021 financial outlook. Turning to the P&L, sustained high revenue growth supported double-digit comparable operating profit and EPS gains.
Operating profit increased 32% as reported, including benefits from the lapping of a $27.5 million G&A charge related to an ongoing litigation matter, which is excluded from our comparable growth metrics. On a comparable basis, operating profits expanded 12% and operating margins increased 20 basis points compared to high prior year levels, which included benefits from pandemic-related cost controls. Gross profit increased 12% in Q3, reflecting strong revenue gains. Gross margins decreased modestly on a comparable basis as benefits from continued high recurring CAG diagnostic revenue growth and moderate net price gains were offset by business mix impacts from high CAG instrument revenue growth and lower LPD and human PCR revenues. We also saw some gross margin impact from investments in our lab business to support high growth and customer service levels.
Operating expenses decreased 2% as reported and increased 10% on a comparable basis in Q3. As expected, we saw a higher level of comparable OpEx growth as we advanced investments in our global commercial innovation capability and onboard the ezyVet acquisition. Q3 EPS was $2.03 per share, including benefits of $4 million or $0.05 per share related to share-based compensation activity. On a comparable basis, Q3 EPS increased 12%. Foreign exchange added $2 million to operating profits and $0.02 to EPS in Q3, net of $2 million in hedge losses. Free cash flow was $354 million in Q3 and $458 million for the first nine months of 2021. On a trailing 12-month basis, our net income to free cash flow conversion rate was 88%.
We increased our 2021 full year outlook for free cash flow conversion to 80%-85% of net income, reflecting a refined capital spending estimate of approximately $115 million, including approximately $20 million in real estate purchases. As we advance plans for 2022, we expect an increase in capital spending levels to support additions to our manufacturing and distribution capacity aligned with our high growth profile. Our balance sheet remains in a strong position. We ended the quarter with debt to EBITDA leverage ratios of 0.8x gross and 0.7x net of cash, with $145 million in cash and no borrowings on our $1 billion revolving credit facility. We allocated $184 million in capital to repurchase 275,000 shares in the quarter.
Turning to our 2021 full-year outlook, we're updating our projected range for overall revenue to $3.185 billion-$3.2 billion. Based on our continued strong momentum in Q3 2021, we're increasing the lower end of our organic growth outlook by 1% and maintaining the higher end of our growth outlook aligned with sustained high two-year annual growth trends for CAG Diagnostic recurring revenues. Operationally, this results in an increase of $10 million in our full-year revenue outlook at midpoint. These improvements are offset by a $5 million FX headwind compared to our last outlook related to the recent strengthening of the U.S. dollar.
Our updated re-reported revenue growth outlook is 17.5%-18%, including approximately 1.5% of full year growth benefit from FX and 0.5% of growth benefit from acquisitions. Our updated overall organic growth outlook of 15.5%-16% reflects an estimated organic growth range of 17%-17.5% for CAG Diagnostic recurring revenue. Other elements of our revenue growth outlook include continued expectations for lower year-on-year LPD revenues in the H2 and for a reduction in human COVID testing revenues year-on-year.
In terms of key financial metrics, we've refined our reported operating margin outlook for 2021 to 28.8%-29%, reflecting expectations for 200-225 basis points of full year comparable operating margin improvement at the high end of our last guidance range. We're planning for moderately lower operating margins in Q4 compared to high priority levels driven by mix impacts and advancement of commercial and innovation investments and target project spending aligned with our high growth profile. We're raising our EPS guidance range by $0.06 at midpoint to $8.30-$8.38, reflecting 26%-27% full year comparable EPS growth. We now estimate FX will provide $0.16 of positive full year EPS benefit, $0.01 lower than our earlier estimates, net of established hedge positions.
We've also refined our overall effective tax estimate to 19%, including an updated estimate of $0.29 per share of tax benefit related to share-based compensation activity. We've provided details on our updated estimates in the tables in our press release and earnings snapshot. As we complete 2021, we're advancing our plans for 2022, aligned with sustaining our strong revenue growth. We're confident we can maintain our excellent supply chain performance to support continued high growth and manage any inflationary impacts in our business while building on our strong 2021 profit results. We look forward to providing specifics on our 2022 financial outlook on our Q4 earnings call. That concludes our financial review. I'll now turn the call over to Jay for his comments.
Thank you, Brian. Good morning. We're pleased to report another quarter of excellent results for IDEXX, driven by sustained momentum in our CAG business. We delivered double-digit organic revenue growth overall, supported by 11.5% organic CAG Diagnostics recurring revenue growth compared to very strong prior year growth levels. Two-year average annual organic growth rates across testing modalities were in line with growth in the H1 of 2021, with clinical visit trends sustaining above pre-pandemic levels. These strong trends are evidence that veterinary practices worldwide continue to focus on elevating standards of care by leveraging IDEXX's advanced product and service platforms. The IDEXX team is doing an outstanding job supporting continued high growth and customer service levels, putting us on track towards 2021 financial performance at the high end of our previous outlook and above our long-term goals.
Today, I'll highlight key areas of progress in our product and commercial initiatives that position us to deliver continued high growth and strong financial returns. Let's begin with a brief update on sector trends. Positive companion animal healthcare trends continued in the third quarter, building on the accelerated demand levels achieved throughout the pandemic. U.S. clinical visit growth was 2% in Q3, compared to strong 7% prior year third quarter growth levels, which included benefits from pent-up demand. To normalize for prior year pandemic dynamics, we are monitoring two-year average annual growth rates, which were 4.4% in Q3, continuing above the pre-pandemic levels of 2%-3%. Wellness clinical visit growth of 6% on a two-year basis points to continued adoption of a preventive approach to pet healthcare.
This sustained underlying momentum reflects the continued strengthening of the pet-pet owner bond, the benefit of stepped up growth in the pet population beginning early during the COVID-19 pandemic through early 2021, and sustained focus in the veterinary clinic on medical services. Around the world, veterinarians' passion for their work, combined with pet owner desire for excellent care, have driven this focus on services as they remain extremely busy. U.S. practice revenue growth in the third quarter advanced a healthy 7% versus the prior year, and an even more impressive 9% on a two-year basis, supported by two-year average growth of 11% in clinical revenue and 13% in diagnostic revenue. Customers are clearly attracted to IDEXX's broad portfolio of product and services to support elevated levels of demand while also growing their practices. These positive dynamics are also true in our international region.
IDEXX's growth is sustaining at an even stronger rate, reflected in the 16% two-year average annual growth in CAG Diagnostics recurring revenues in Q3, a premium of nearly 1,200 basis points above two-year average clinical visit growth rates. High levels of execution and consistently strong sector trends reinforce our confidence in sustaining strong growth momentum as we finish the year and build our plans for 2022. Outstanding commercial execution has been a key driver of our business performance, and our team continues to support our customers at a high level. This is evidenced by 36% year-on-year growth in premium instrument placements in Q3, a record number of third quarter placements for the company. High growth across our Catalyst, ProCyte, and VetLab platforms supported a 14% overall year-over-year increase in our premium install base.
Veterinarians are using IDEXX's diagnostic tools to build capacity and improve efficiency within the clinic to support future growth, which is also reflected in high levels of second Catalyst placements and continued strong 16% gains in Catalyst placements at new and competitive accounts. Our strong global instrument placement momentum has long-term benefits and gives us further confidence that future consumable streams will also support continued strong growth. These results were achieved despite continued constraints on direct access to customers. Time for our customers is a scarce and valuable resource. In-person sales trends remain at approximately 60% in the U.S. and slightly lower in Europe at over 50%. Despite these constraints, our teams earned high levels of connection to our customers to deliver exceptional results by leveraging their trusted long-term relationships as highly relevant partners.
We continue to enhance our commercial capabilities through rolling country-level expansions of our field sales force to build on these results and to address the significant opportunities ahead of us. We've completed our expansions in Germany, France, and South Korea, and are seeing significant positive traction in instrument placements and CAG recurring revenue growth in these countries as a result. In addition, we are expanding our footprint in three additional countries, as noted on our last call, with hiring, onboarding, and training tracking well to our plans in those areas. We expect to be live in all second wave countries by the end of Q1 of next year. In addition to our commercial footprint, we made progress in the past quarter in expanding our service footprint and capabilities in order to better support international business and customers.
This included targeted investments to expand our European reference lab network and enhance our telemedicine services. These capabilities will support our long-term growth goals by ensuring we meet our customers' needs with a broad network and comprehensive portfolio of services, complementing our world-class reference lab facility in Kornwestheim, Germany. These advancements support high growth across our testing modalities as customers continue to take advantage of the flexibility offered by our customer-centric programs, such as IDEXX 360, to grow their businesses and elevate standards of care around the world. Innovative products like ProCyte One are helping to build on this momentum. We've seen a very strong response to ProCyte One, having delivered over 1,000 units worldwide since launch and on track for the approximately 4,000 annual worldwide premium hematology placement pace we shared during Investor Day.
Feedback from customers of all sizes have been overwhelmingly positive as they rave about ProCyte One's easy use, low maintenance profile, and excellent performance. Our growth trajectory now reflects launches in all four of our major regions, with a select number of country launches remaining in the fourth quarter of this year and into 2022. ProCyte One provides a great opportunity for increased engagement with customers, supporting strong adoption of the new platform globally and a broader expansion of our business relationships. As an example, almost 95% of worldwide ProCyte One placements and nearly 100% in North America have either included a Catalyst One or been placed at a customer that already has a Catalyst One, demonstrating the strong multiplier effect of this innovative product. Our rapid assay business is another area which provides an opportunity to expand relationships with customers around the globe.
Rapid assay test revenues grew solidly in Q3 compared to a very strong prior year and 14% on a two-year basis, with comparable gains in the U.S. and internationally. Vector-borne disease testing, a critical component of the rapid assay business and of wellness testing in the U.S. more broadly, was the primary driver of this growth as tick-borne disease becomes more prevalent in regions around the U.S. This testing growth continues to be supported by the SNAP Pro instrument, which helps drive engagement and loyalty through enhanced insight, accuracy, and practice workflow benefits. Double-digit growth in the SNAP Pro installed base in the U.S. and internationally. In recent innovations like critical decision support, which aids increasingly busy veterinarians in making critical decisions when faced with a positive test, have helped drive excellent 97% customer retention levels within the rapid assay business.
Our innovation strategy is also reflected in the expansion of our cloud-based software capabilities, which benefited from the Q2 acquisition of ezyVet. The integration of ezyVet into our software portfolio is proceeding to plan with high customer enthusiasm. The ezyVet acquisition helped drive 33% reported growth of veterinary software, services, and diagnostic imaging systems revenue in the third quarter, which was further supported by strong 15% organic growth in our core software and digital imaging products. This growth reflects solid double-digit year-over-year gains in our profitable recurring revenue software products. It also demonstrates the benefit of a growing installed base of PIMs in industry-leading low-dose diagnostic imaging products. Cloud-based offerings represent the majority of PIMs placements at over 80%, as cloud-based offerings provide performance, quality, and lifecycle cost advantages.
Within diagnostic imaging, recent updates to the Web PACS product include additional features important to specialty practices and deeper, more seamless integrations with PIMS systems. With a growing installed base and very high retention levels, IDEXX Web PACS has become an important part of our enterprise software ecosystem. Product enhancements like this and others aimed at making critical workflow and customer communications easier and more efficient are an impactful example of how our technology for life approach is supporting busy practices. Our commercial sales force and marketing teams continue to balance product sales with advancing the IDEXX preventive care program, which provides a structure and incentive for our customers to continue driving wellness testing and raising the standard of care.
Enrollments in this program in the third quarter, despite constrained in-person discussions with customers, sustained at a rate similar to the second quarter as we executed approximately 150 new preventive care enrollments and continue to track towards our goal of 10,000 engaged customers in the U.S. by 2024. In addition to strong commercial execution, our consistent growth trajectory also reflects resiliency and agility in our supply chain. This has enabled us to weather the impacts of the COVID-19 pandemic and meet the strong demand within our sector. IDEXX benefits from a number of factors related to our business, including strong long-term supplier relationships, nearshoring and product standardization, and inventory buffers. These factors and our proactive approach managing frontline operational processes have allowed us to achieve 99% customer product availability through the pandemic, resulting in high customer satisfaction and increased retention.
We believe we are well-prepared to support sustained high growth and service levels in our business going forward. While there may be relatively higher costs in certain areas to support our growth plans, we are confident we can manage these impacts effectively through our operational capability and focus while building on our strong financial performance. Overall, we feel very positive about our continued strong business momentum as we engage with and support veterinarians around the world who are advancing the care standard. Looking forward, we are proceeding with plans for sustained high growth aligned with our long-term growth potential as current momentum positions us well to support investments in the infrastructure, solutions, and commercial capabilities necessary to achieve the significant opportunity ahead of us while delivering continued strong financial performance. Finally, I'd like to thank our employees and our customers for their perseverance and flexibility during these dynamic times.
I'm extremely proud of what we've accomplished together and look forward to continued excellence in the future. That concludes my remarks, and we now have time for questions.
Thank you. We'll now begin the question-and-answer session. If you do have a question, press star then one on your touch-tone phone. If you wish to be removed from the queue, please press the pound sign or the hash key. Once again, if you do have a question, press star then one on your touch-tone phone. Our first question is from Michael Ryskin from Bank of America.
Right. Thanks for taking the question, guys. Had a lot of comments in the prepared remarks on strong instrument placement trends, you know, particularly in ProCyte One, it's in the cross zone you've been able to see there. I'm just wondering, are you able to see sequential acceleration there and any increased uptake of SediVue, if you could clarify on that? Just especially in some of those markets, you're seeing incremental competitive introductions by some of your peers. I'm just wondering if you could talk on dynamics and what you've been able to see from others in the marketplace.
Yeah. Good morning, Mike. The Q3 was a record placement really across our premium instruments, hematology, chemistry, SediVue. We think in part what's driving that is you know, less pent-up demand and more practices really investing in their practices because they're busy, they're looking for technology that can support productivity and obviously greater patient flow. With respect to ProCyte One, you recall, we launched in the U.S. in late Q1 and then internationally in late Q2. We've seen very rapid uptake. The majority of the ProCyte Ones, the vast majority of the ProCyte Ones either have gone into competitive accounts with Catalyst or into existing Catalyst accounts. It's a real customer pleaser.
I think it's delivered on all aspects of the brand and product promise, ease of use, performance, great cost profile. Keep in mind, it's also part of our pay-per-run and auto-replenishment model. We're excited about the opportunity. If you recall from Investor Day, we identified, you know, almost 100,000 placement opportunities globally, two-thirds plus of that internationally. We're just in the early days of getting started on that. Very promising outlook for hematology. With respect to SediVue, we continue to make excellent progress in SediVue. Obviously, instrument placements were high 30%+ . We saw a nice uptake in the U.S., a nice sequential progress internationally.
Great. Thanks. If I could ask a follow-up, just on trends you saw over the course of 3Q and as we think about 4Q. If we look at the snapshot in clinical visit growth and revenues per visit, obviously you have the much tougher comps from a year prior, but that should continue going forward into, you know, 4Q and 1Q next year. As we look at the two-year stacked comp on recurring CAG Diagnostics and total CAG revenue growth, are there any other dynamics we should be mindful of as we think of going into 4Q besides the comp dynamic? Anything else you're seeing in terms of changes in the marketplace or visit growth, volume growth, things like that?
Morning, Mike. I think the bigger theme that we're highlighting is the CAG Diagnostic recurring growth trend on a two-year basis really held up quite well in the third quarter. I think as you know, you get into these year-on-year comparison dynamics, so we're focusing a bit on the two-year trend to calibrate. We saw that 16% two-year average annual growth level, both in U.S. and international. You know, I think that's also the premium on a two-year basis held up very well. It was 1,200 basis points in Q3. I think that is the bigger trend that aligns with the higher end of our revenue growth outlook, and that's informing our posture heading into next year that we're really planning for sustained strong growth.
We're investing towards that, ensuring that we have high service levels. In terms of broader trends, I think Jay can provide some color, but I think the clinical visit trend was moderated a bit from the H1 on a two-year basis. We may be seeing some plateauing of the incremental growth benefit we saw from the step up in new pets, although, you know, the pet population has expanded and sustained. Perhaps it might be reflective a bit of clinics just being quite busy. I think it was quite, you know, overall modest and our own trends have held up quite well.
Yeah, just to build on that, Mike. You know, all indications are that demand in the marketplace and the trends remain very strong. You know, clearly, the one-year growth rates held up quite well. If you think back to Q3 in 2020, there was a lot of pent-up demand. There was increased pet patient visits. Really nice growth across tough compares. You know, the two-year clinical visit trends, as we've talked about at 4.4%, is clearly above pre-pandemic levels at 2%-3%. If you take a look at how we've translated that, you know, in our own business, 16%, you know, globally, CAG Diagnostics recurring revenue, U.S. and internationally, those are two-year figures. We've seen nice growth across all modalities, whether you look at, you know, the one-year or two-year.
I think our execution as a company has been excellent. I think the growth momentum remains quite strong. As Brian indicated, we're really positioned to support faster growth by expanding capabilities commercially, innovation, really expanding the resiliency and capacity of our supply chain and manufacturing network.
Great. Thank you so much.
Our next question is from Nathan Rich from Goldman Sachs.
Hi, good morning. Thanks for the questions. Maybe following up on the last one, Jay or Brian, could you maybe, you know, how do you feel about like vet practice capacity right now? I don't know if you feel like there are any labor shortages that are impacting just overall volumes of vet clinics, but it'd be great to get your perspective on where you think kind of vet practices are kind of operating at this point.
Good morning, Nate. Vet practices are clearly very busy. They, you know, there are a number of things that they've done, I think, on a short-term basis to be able to provide additional capacity. A lot of practices are working longer hours. They're hiring more staff. On a short-term basis, they can hire, you know, let's say, associate veterinary technicians and train them. You know, the more trained, higher-level skilled staff obviously takes a bit more time. A number of practices have been able to really improve, make some workflow improvements and adjust capacity just by adding things like exam rooms and things like that. From the standpoint of what we can do as a company, there's a number of really, I think, positive opportunities for us.
Obviously, we provide technologies, analyzers, tools, software that practices can invest in that help them perform both at a higher medical or clinical level, but also more productively, whether it's communications internally or with pet owners or really improving staff productivity. I think evidence of that is in the very significant step up in instrument replacements that we've seen and very fast growth in software PIM systems and ancillary systems that work with PIMs.
Great. That's helpful. Maybe a follow-up for Brian. You know, how should we think about the right, like, baseline level for operating margins as we head into next year? You know, the cadence this year has been a bit unusual with the elevated margins in the H1 of the year. I think the back half, the guidance implies maybe around 26%. You maybe talked about the investments, but could you maybe kind of flesh out, sort of what you think the right, you know, starting point is for, as we think about, you know, the margin trajectory into 2022? Thank you.
Sure. On a full year basis, I think we said 28.8%-29%. We do have some quarterly differences in margins normally. I think Q2 tends to be our highest with just some of the wellness testing that goes on, rapid assay sales and things of that nature. You know, I think we feel good about the growth trajectory in the business, particularly the growth on the CAG recurring revenues. You know, that's a key driver for us, and that really gives us the ability to reinvest and to build on the margin performance that we've had. I think we are intending to invest. We have been investing in growth aligned with the higher growth profile when...
We wanna build on that. We see that as a very high return area for us, particularly areas like commercial investment. We get a very quick payback on that, and we're really pleased with the progress we had in our initial wave of international markets, and we'll look to do more with that next year. You know, we'll provide more clarity on that as we get into the year, but our goal is to build on the strong performance that we had this year and the strong growth trajectory in the business really gives us an opportunity to do that.
Our next question is from Jon Block from Stifel.
Great. Thanks, guys. Good morning. Brian, maybe just to start, the gross margin trend, it was, you know, down for the third consecutive quarter. I know you called out some mix headwinds, ongoing investments, but just wanna go back to the, you know, the big deck from the Analyst Day. You talk about gross margin. I'll sort of frame it as that double up green arrow long term. I'm just curious, does that double up green arrow take hold in 2022, or should we think about some of these investments, you know, really spilling out into the next several quarters?
Yeah, John, I think it's important to calibrate on just what we're working through. If you go back to last year and just looking at our numbers and year-over-year improvement on a comparable basis, we were up over 200 basis points in Q2, Q3 last year. You know, we're comparing to some higher numbers, you know, in terms of the levels we were at last year where we had really constrained kind of cost conditions. You know, I think that's a key factor. We are investing back now and we're seeing that paying off in terms of high service levels and growth. I think we've had some, you know, impacts from mix through the, you know, excellent instrument placement growth has a little bit of a mix headwind for us.
You know, those are factors we're working through. I think the overall dynamics in margins are something that we, you know, believe we can build upon. We'll provide more insight into that as we get into next year. You know, I think that longer term trend, the key driver there is our strong CAG diagnostic recurring revenue growth rates, and we are, you know, well positioned to build on that, you know, with the trends that we've seen in the business. I think that longer term story still holds for us.
Okay. Just to follow- up, maybe just push you a little bit on the 2022 trends in CAG recurring. The 16% CAG recurring two-year average, you know, has been remarkably consistent for the first three quarters of 2021. The guide implies a slight step down in the fourth quarter of 2021. Is that slight deceleration the way to think about the CAGDX two-year slope as we head into 2022? To maybe sort of layer on top of that, is there an opportunity for you guys, you know, for price to play a bigger role in CAGDX into 2022 just based on what we hear from some of the practices on their recent ability to realize price? Thanks, guys.
We didn't provide specific guidance on Q4, but I can tell you that our high end of our range is consistent with the trends that we've seen on a two-year basis on CAGDX recurring for the first three quarters. That is reflected in the guidance. The overall organic growth, just keep in mind, we're up against a little tougher compare on instruments in Q4. You know, it's not a change in trend. It's just we're working through some compares there. It's, again, the high end is largely consistent with where we've been trending. You know, I think that we're gonna learn more on this as we move forward. I think we're really pleased with the execution in the business.
I think the momentum on our key initiatives, particularly things like instruments, give us a lot of confidence that we can build on the strong consumable growth. I think our execution of other modalities is very strong as well. You know, we're watching the market trends, and I think that it's very encouraging. I think there, like I said, there may be some moderation in terms of the step-up in things like that population growth, and we've gotta pay attention to capacity at clinics and things like that. Those are good problems that we think we can help our customers with.
We're, I think, that's been the key theme, hopefully you hear today, is that the trends in the business we're very pleased with, particularly in the CAG business. We were looking to invest to build on them.
That price realization, Brian, if I can just circle back on that. Sorry, do you think there. That's, that one's a bigger opportunity?
Sorry about that, Jon. We've been in that 2%-3% range. I think that is an area that we're gonna continue to look at. Pet owners are willing to pay more for services over time. There may be some select inflationary pressures in the business here, you know, in things like some input costs and labor and freight. We're paying attention to that. I think it is something we can look at over time if we see some sustained, you know, impacts on those fronts. Like I said, I think the market backdrop, the industry backdrop gives us an opportunity to look at that just given the strength of the pet-owner bond.
Perfect. Thanks, guys.
Our next question is from Chris Schott from J.P. Morgan.
Great. Thanks so much. Just two for me. I guess first on in-person vet access. I think you mentioned in-person access now in the 50%-60% range. As that number moves higher, is that a meaningful benefit for your business, or have you found that you're able to do pretty much everything you need to do given the access as it is today? Just have one follow-up after that.
Yeah. Good morning, Chris. We're up around 60% in the U.S., 50% outside of the U.S., and we think that can grow. Yeah, that will be higher as we work through, hopefully, the tail end of the pandemic. You know, I think we've gotten very good at really segmenting what should be done or what is best done in person versus virtually. You know, we've been able to, you know, I think, pretty much do all that we need to do virtually. There are some activities like whether you're introducing product or visiting competitive accounts and building and, you know, I think strengthening relationships are better done in person. You know, we think that over time, that will increase.
It's not gonna go back to 100%, but it'll be something less than that. I think it will benefit our preventive care initiative, where we know practices are not only, you know, very busy, but I think repeated access is helpful in being able to, you know, sell and partner with customers, you know, with that program. Do we expect, you know, over time that really step up to pre-pandemic levels.
Okay, great. Just come back to the topic of inflation. Just as we think about this kind of new inflationary environment. Are you seeing or do you expect to see in the near term any either gross or operating margin pressures due to this? I think you mentioned that if this is more sustained, there might be an opportunity within, on the price side to address. I'm just trying to think in the nearer term, is that something that's noticeable in the numbers, or is there abilities to offset that, elsewhere in the business?
This is Brian. We have seen some, you know, inflationary impacts in the business. I think it's been more in areas like freight and distribution, which I think a lot of companies are experiencing. For us, it's relatively selective on input costs, things like electronics and resins and, you know, we're paying attention to labor costs as well. I think those are all, you know, important areas for us. You know, we've been able to manage through those effects well, and we're really focused on sustaining high levels of service to our customers, particularly in this high-growth market. You know, that's our focus and our intent.
I think we're confident that we can build on kind of the profit trends that we've had while managing through those kind of effects on our business.
Great. Thanks so much.
Our next question is from Ryan Daniels from William Blair.
Hey, guys. Brandon Vazquez speaking for Ryan Daniels. Thanks for taking my question. I guess to start, given kind of the lack of bandwidth in the vet offices and the kind of constraints on the capacity, how has that kind of affected the, you know, the selling process and things like, product education? Has that affected it negatively at all, or have you been able to kind of work around that?
Yeah. Good morning. You know, as I had previously indicated, you know, practices are extremely busy, and it has affected how we do our sales calls. You know, once upon a time, you could get a fair amount of time with the veterinarian, you know, and her or his or her staff, and I think we've. We try to be very efficient in what, you know, previously we may have had 40, 50 minutes that we're able to accomplish in 20 minutes. We've adjusted accordingly. We, you know, have provided tools to our sales organization so that they're productive and they can get to the point.
We continue to provide, you know, a lot of training, including CE training virtually into the webinars to our customers so that they can, you know, get the training they need when they have some free windows and moments. We try to be, obviously respectful but very efficient when we do call on practices. Because, you know, I think most practice and practice owners consider us highly relevant, you know, to their success. They, in large measure, provide time when we meet with them and, you know, I think with good results.
Great. Thanks. Then on the capital instrument side of things, would you say you kind of, you know, worked your way through most of the backfill and a lot of this growth is, you know, now kind of incremental, you know, practices that kind of realizing that they need an addition of a ProCyte or an additional Catalyst or that sort of thing?
Yeah. I think this capital performance we've seen is not pent-up demand. It really represents investments that practices are making in their capacity and really it improved capacity and productivity of their practices. I think it's just a solid reflection of demand trends.
Great. Thanks.
Our next question is from Balaji Prasad from Barclays.
Hi, good morning, and thanks for the questions. A couple of them. Firstly, just saw that you did comment on increased testing for ASF. I wanted to understand if you have visibility into what has led to this and see if there's any broader read-through to ASF trends. In other words, can an increase in testing signal that ASF incidences are spiking up, spiking again? Secondly, I'm not sure if you answered this, but have you seen any supply chain disruptions? And which of your segments would be or could be most exposed to the current global supply chain challenges? And lastly, if you can you just help us understand the CAG dynamics better, trying to correlate the same store revenue growth, which is five percentage points above the visit growth of 2%.
Is this all linked to higher utilization, or was there any component of pricing which is above normal trends? Thank you.
Why don't I take your first question on African swine fever. The primary dynamics we've seen are in our China business for LPD. We saw a significant step-up in program testing in support of addressing African swine fever last year. Those trends have changed. There are changes in the local management of the disease in China, where there is now the local farmers are allowed to harvest the animals rather than. That's leading them to harvest them rather than treat the disease. There's been a decline in demand, and that's raised some compares for us.
For our business, that's been the primary impact of African swine fever, and we're anticipating that's gonna continue to be a challenge for us year-over-year for some upcoming quarters.
I'll speak to the supply chain. I think resiliency and performance of the business, which has been excellent. You know, as I previously indicated, we have excellent long-term supplier relationships. We've been able to leverage those and make sure that we're very well provided. Most of our manufacturing or almost all of our manufacturing is, you know, local. We're near shore, and we have a great deal of product standardization and maintain high inventory buffers. We've been able to really support very high product availability throughout the pandemic. Our customers have clearly appreciated that and have rewarded us, you know, with their business. We feel very positive about our ability to continue to do that going forward.
I believe your third question was on utilization at the clinic level.
Right.
What we point out, if that was correct, is the on a year-over-year basis, again, you get into these compares with last year where you had a big step-up in you know wellness testing and pent-up demand. The bigger driver of growth in the third quarter year-over-year was utilization growth. The utilization gains at the clinic level have remained quite strong and on a two-year basis, good one-year growth. It was you know more than offset kind of flat frequency that was more related to the year-on-year kind of compares in terms of the testing number of visits.
Okay. With that, I'd like to thank everybody for calling in. I'd also like to address the broader IDEXX team, some of which are on the call, and say thank you for their continued extraordinary performance. Our employees have demonstrated unwavering commitment to our purpose and excellent ability to execute against our strategy, and I truly appreciate all their efforts. With that, we'll conclude the call. Thank you.
Thank you, ladies and gentlemen. This concludes today's conference. Thank you for participating, and you may now disconnect.