Ladies and gentlemen, thank you for standing by, and welcome to the Quanterix Corporation Q3 2021 earnings conference call. At this time, all participants are in a listen-only mode. After the speaker's presentation, there will be a question and answer session. To ask a question during the session, you will need to press star one on your telephone keypad. If you require any further assistance, just press star zero. I would now like to turn the call over to Quanterix Chief Financial Officer, Michael Doyle. Please go ahead.
Thanks very much. Good afternoon, everyone, and thanks for joining us today. With me on today's call is Kevin Hrusovsky, our Chairman and CEO. Before we begin, I would like to remind you about a few things. The call will be recorded and will be available on the investor resources section of our website. Today's call will contain forward-looking statements that are based on management's beliefs and assumptions and on information available as of the date of this call. We may not actually achieve the plans, intentions, or expectations disclosed in our forward-looking statements. Forward-looking statements involve known and unknown risks, uncertainties, assumptions, and other factors that may cause our actual results, performance, or achievements to be materially different from any future results, performance, or achievements expressed or implied by the forward-looking statements.
The risks and uncertainties that we face are described in our most recent filings with the Securities and Exchange Commission. During today's conference call, we will discuss some financial measures that are not presented in accordance with U.S. generally accepted accounting principles or non-GAAP financial measures. In the Q3 earnings release and in the appendix of our presentation, which are available on our website, you will find additional disclosures regarding these non-GAAP measures, including reconciliations of these measures to comparative GAAP measures. We believe that these non-GAAP financial measures provide investors with relevant period-to-period comparisons of our operations. These financial measures are not recognized under GAAP and should not be considered in isolation or as a substitute for a measure of financial performance prepared in accordance with GAAP. With that, I will turn the call over to Kevin.
Thank you very much, Mike. On slide three, you see the agenda. I'm gonna talk about our accelerated growth opportunity and also what I consider to be some of the transformation around utilizing our Simoa franchise to enable therapeutic drugs. Mike will then do some financial results summaries, and I'll then close the meeting with an update to the objectives that I updated after our last earnings call so that you could see some of the advances that we're working towards between now and year-end. To start, we showed this slide last time. Blood-based biomarkers are fast becoming a gold standard surrogate for traditional tau and Aβ PET imaging. You may have been reading that ever since the FDA approved Biogen's drug and Eisai's, they basically have become a buzzword.
The biomarker has become a buzzword as a way to help evidence efficacy and also evidence, in some cases, safety. I'd like to start off on slide five by showcasing the fact that we received at a record pace a Breakthrough Device Designation from the FDA for our p-tau181 blood-based assay, which will be utilized primarily with other modes of diagnostics, including imaging to help triage patients, is the intent for this application that we've been given the Breakthrough Device Designation, which gives us a priority with the FDA. There also was some really important publications, namely in The Lancet, the Simoa diagnostic accuracy data were published. Also p-tau217, which is a next generation of phosphorylated tau that we're also working on.
Lilly showcased that they used it in TRAILBLAZER-ALZ 2, and they have also been given accelerated pathway for their drug. They actually showed that it correlates p-tau217, both with the images, the PET images, as well as clinical benefit, which is a pretty significant advance. On the financial results, on a non-GAAP basis, we grew at nearly 50%. Year- to- date, we've been growing, actually a little greater than 60% on a non-GAAP basis. Basically, the difference between GAAP and non-GAAP is removing all of the one-time items from GAAP to give us the non-GAAP. In 2021, our utilization of consumables has actually been increasing fairly formidably. We've been running at least the 60% level, which is significantly beyond our expectations going into the year.
We do have $411 million of cash balance at the end of Q3. You know, our value creation chain reaction has really been kicked off by utilizing biomarkers in trials and then getting them validated, particularly for Alzheimer's trials. Then the utility being an opportunity for us to transition over into diagnostics, where there's a need for scalable blood-based testing of Alzheimer's to be able to really at a full-scale level be able to move patients into the drug and then monitor for drug performance. This is an area of opportunity.
We also, interestingly, were able to get very good progress on our EUAs in the COVID landscape, and that's how we really got to know the FDA pretty well by being able to get an asymptomatic reading on COVID saliva test for the Delta variant for antigen. This is a pretty significant breakthrough. There's also been a couple major webinars that further reference Quanterix, especially University of Emory , showcasing how they've deployed four of our HD-Xs and measured over 120,000 saliva points for COVID. This is the kind of advance that we are continuing to try to pursue. When you look at our financials on slide six, you can see that we had the 46% growth, very good movement on the non-GAAP basis.
What's also really impressive is the product growth, both instruments and consumables in Q3. Consumables, particularly almost 100% growth. Lab services, which we had projected would be down this year compared to at least last year, we had, you know, very significant one-time events of COVID. We knew for the full year, we would probably be about the same level of lab services as 2020. On a, you know, two-year CAGR from 2019 to 2021, we are continuing to progress at an 18% level, so we are still seeing nice growth.
Overall, I would say the RADx and the Abbott licenses, both from last year, and then this year having RADx, those being removed from our GAAP performance to create non-GAAP allows you to see the real growth of 46% in Q3. On a margin basis, on slide six too, you can see that our Q3 delivered almost 55% gross margin, up from 51.5 last year. On a year-to-date, same type of performance, interestingly, consumables is actually over 100% growth, and instruments is over 70% growth. The lab services is basically flat with last year for the first three quarters of the year, but on a CAGR basis, it's up 24%, the two-year CAGR from 2019 to 2021.
Once again, you can see that our gross margins for the three quarters have gone from 48.4% up to 56%. When you look at the demographics on slide eight, you'll see that geography, we continue to be very strong in North America, but also evolving very nicely in Europe and Asia. Primarily, we see a lot of our position increasing in pharma CROs, but we continue to get a lot of publication pull-through through our academics. You can see we've had very strong growth in academics so far in the last 12 months as well. In neurology, you can see we are up over 100% in the last 12 months, and that is really the area that we're honed in on.
You can also see in consumables over the last 12 months, we're up nearly 100%. Accelerator down slightly over that 12-month period, primarily due to the one-time effect in the previous year. Instruments, you know, greater than 50%, which is a very strong indicator for future consumable pull-through growth. On slide nine, you can see that the publications, which is the way we validate, third-party validation of our technology, and that continues to accelerate, and we're nearly 1,500 third-party peer review publications now. We have over 650 instruments now installed around the world.
You can see in the Accelerator, even though we do know our growth this year is not gonna be like it's been the last 12 months due to COVID, we still have up to 160 phase I through III trials that have been run in our laboratory. On slide 10, I'd just like to showcase that we started out in research. We really started this company in research in neuro, and then we've moved very productively into antigen serology for COVID and research. We've utilized the technologies that we've got for COVID in creating the diagnostics, and that's how we got the two EUAs, one for serology, one for antigen.
We're now taking those advances that we showcased at Emory, working with the NIH, who gave us $20 million to scale up given our capabilities, that we're now moving that down into Alzheimer's, and that's where we got the breakthrough designation for phosphorylated tau. As I think you'll see in the updated objectives, we also plan. We updated these objectives at the end of Q2, but we said at that time, we would also submit by year end the MS NfL for breakthrough designation. That's another key advance for us in our overall objectives for the second half. You can also see on slide 13 that we continue to have really strong growth catalysts in our research business.
This breakthrough designation for 181 is causing many customers to wanna utilize our technology for their drug trials, given our you know access and our direction moving into the clinic. This has also further represented the drug trials being revitalized using biomarkers, given the success finally of Aduhelm being approved by the FDA with the fact that the accelerated growth path for Lilly's donanemab. We're pretty excited that the whole industry is now revitalized on Alzheimer's trials. That puts a lot of pressure on us scaling our company and also making sure the HD-X is ready for clinical use, expanding our Accelerator, and we think seeing Alzheimer's even earlier before cognitive impairment is benefited by the HD-X.
You're gonna see that we are planning to accelerate a lot of our investments to really bring these four items into a very sharp focus of opportunity in 2022 and 2023. You'll see us making additional OpEx investments particularly around you know these four items in the fourth quarter in 2022. Also on the right-hand side, you can see that this is the diagnostic where we do believe the TAM is about 10 times the size of the research TAM, and we see mounting evidence of these plasma phosphorylated tau biomarkers for Alzheimer's, creating a significant opportunity on the diagnostic side. It's a much sharper focus.
We see a lot more value and potential, maybe with greater risk, but if we can get an Alzheimer's plasma test into the market via the breakthrough designation, it represents a way to triage, screen, and diagnostically improve the scaling and even monitoring of patients with Alzheimer's with our biomarkers. For that reason, we're accelerating our LDT footprint in our Accelerator and believe that we will be able to run LDT, and you'll see a later slide in 2023 at the latest. Payer leapfrog for health screens, we also think is a big growth catalyst longer term for our diagnostics business opportunity.
Slide 11, we've shown over the years, it basically shows that by increasing the sensitivity, it's a significant opportunity to take the IVD proteins today that are measured by Abbott, Roche, and Siemens. There's about 200 of them, collecting about $25 billion, almost all of that being singleplex and a large proportion of it being after patients have symptoms. By being able to move earlier before symptoms and to even create multiplex for greater disease specificity, we think we can move the number of IVD proteins over the next 20 years from 200 proteins to as many as 1,000, significantly ramping up the opportunity for diagnostics of protein measurement. To do that noninvasively before symptoms, which we think creates a chance to revolutionize healthcare.
We think that the fueling of that will come via the research products, where today there's 1,300 proteins that are being analyzed. We think with a lot of new entrants into the industry, where there's gonna be a chance to significantly ramp up the number of proteins that are tested from a research standpoint. Slide 16 and 17 basically show you that the sensitivity is what really is enabling in the area of neuro and cancer, the ability to see the disease before symptoms present and to do it noninvasively in blood, saliva, and urine. Our goal would be to truly get utility from this technology in a diagnostic setting with this noninvasive, sometimes home care sampling for testing that is very much noninvasive for even if there's infectious disease that might plague society.
If you can give home care testing, and or at least sampling, and then see disease before symptoms, it has a profound effect on the overall opportunity. In slide 19, we are simply showing that traditionally, the diagnostic industry is $30 billion in revenue roughly, and the pharma industry is more like $300 billion, 10 times the size. You can see that many of the pharma and diagnostics do a lot of research on antibodies and proteins that lead to this incredible two markets for life sciences. And inside of this, we're showing the brain and all the different biomarkers that we now can see in blood. Some of them we're actually multiplexing and advancing the field for both diagnostics and pharmaceuticals.
We think there's a whole new category, neurodiagnostic therapies, that's really about getting the therapy into the patient before symptoms. We think that the earlier you can get these diagnostics to teach you when a patient has the pathology, and you can then deploy the drug, you can do it safer and with greater efficacy, is a lot of what we're seeing drug companies now attempting to achieve with our technologies. On slide 20, you can see that the TAM over on the left-hand side, when it's simply a research biomarker for Alzheimer's, is really only like $ half a billion for the drug trials. We do have the probability, we think, of significantly increasing the probability of a drug getting approved by using these biomarkers for earlier phase disease.
In the center, you can see one of the game-changing publications that came out, where it showed that you could actually create correlations by measuring in blood our biomarkers with what you used to see in a spinal tap sample result as well as a PET image or an MRI. That breakthrough of that correlation, we think, has allowed a much lesser invasive, high throughput approach to move into utility and diagnostics, which we think the TAM could be as much as $11 billion versus the original $0.5 billion. That's a lot of what we're focused on is trying to capture 10% of those TAMs someday. On slide 21, Lilly has gotten the accelerated pathway for their drug and they are utilizing our technologies as they've stated in their press releases.
We're really excited to see if we can continue to evolve it. Slide 22 just shows that the area under the curve for our phosphorylated p-tau181, where we got the breakthrough designation. Third-party peer-review pubs show that the area under the curve is 80% roughly if it's before cognitive impairment. It's as high as 90% after you start to see cognitive impairment. That's why we wanna continue to advance our sensitivity, because on Slide 23, you can see there's different biomarkers that can measure pathology, disease pathology, sometimes as early as 10-15 years before dementia starts. The earlier you can see this pathology, the better chance drugs have of being approved using these biomarkers, as well as longer-term, moving patients into these drugs, utilizing these same biomarkers.
On slide 24, we just want to show that today there's 55 million people that have Alzheimer's with dementia, and it's projected by 2050 to be 152 million, three times the level. If you just assume that 10% of the world has access to diagnostics and that those that actually get diagnosed with Alzheimer's would utilize our technology four times a year to make sure that the biomarkers are progressing, it would suggest that a TAM could be as large as $7.5 billion today, and someday as large as $22.5 billion, with the emergence of greater levels of age and population around the world and the greater population of Alzheimer's.
On slide 25, we just show that our overall approach is to start out with an LDT, which we're saying conservatively, we feel like by the end of 2023, there's an opportunity to be an LDT for Alzheimer's using our phosphorylated tau 181 and/or even beyond that in a multiplex for even greater specificity. We think there's an investment of $10 million-$15 million to achieve that. And then to get a single site IVD or a laboratory IVD, which has FDA approval, that gives you the dual source of reimbursement of Medicare with the actual regulatory approval, we think it's more like $40 million-$60 million, and we feel like by 2024, this is achievable, if we can continue advancing the way we are.
Ultimately, we do think distributed IVD would be beneficial for the Alzheimer's landscape, and there, a new platform would be required. We have relationships, as you know already, with Abbott, and we also have an NFL relationship with Siemens. Maybe this is done via partner, but there's probably as much as $100 million required to achieve those TAMs that you see on the right-hand side. Up above at the title, we basically say, you know, partnering this could further de-risk and accelerate our ability to get into the diagnostic landscape. Initially it's triage, but ultimately as a screen. We're pretty excited that we are making these advances, and we would like to increase our investment given that the certainty has been improved.
What we don't know right now is from a clinician's perspective, will rule out the way in which many neurologists wanna use the test, which would need to maximize sensitivity or would rule in saying that for sure this patient has Alzheimer's, which would require maximum specificity. We think that both of these are achievable with different cutoffs with our technology, and that's a lot of what we're trying to deploy right now. You know, finally, I would say that we did say that we would plan sometime, as I said in the update of the second quarter objectives, we would plan sometime in 2022 to file, you know, for MS breakthrough designation. That remains our goal for the second half, and to make sure that that's done completely in the second half. With that, Mike, I turn it back over to you for some financial review.
That's great. Thanks, Kevin. I'm gonna provide some additional financial details about our third quarter 2021 performance. For your reference, for those following the call, it'll be slide 27. As Kevin noted, our GAAP revenues in the third quarter of 2021 was $27.7 million and included $1 million of revenue from our RADx awards. Excluding this non-recurring item, our non-GAAP third quarter 2021 revenue was $26.7 million, a 46% increase versus the prior year third quarter non-GAAP revenue. We had record product revenue in the third quarter of $20.7 million, an increase of 77% versus third quarter of 2020.
Within product revenue, consumables revenues grew 98% in the third quarter versus the prior year third quarter to a record of $14.2 million, driven by our strong demand for p-tau181 and our NeuroMultiplex assays. Like Q2, our revenue performance in Q3 may include some recovery of previously deferred demand due to pandemic as customers return to more normal operations. Service revenue decreased 10% in the third quarter to $5.9 million. 2020 was a strong year for services revenue as one-time COVID-related activities forced lab closures and drove increased activity to our Accelerator lab. Looking at our business revenue over two years, the CAGR, as Kevin mentioned earlier, just for the third quarter was 18%, and it's 24% on a year-to-date basis. Year-to-date total revenues are $80.3 million.
Excluding revenue from our non-recurring RADx awards, non-GAAP year-to-date total revenues are $76 million, a 61% increase from the year-to-date 2020 non-GAAP revenue. Stated previously, we are not providing revenue guidance. Customer activity has returned to pre-COVID levels. However, potential renewed spread of new variants could force renewed lockdowns, potentially impact installations and utilization. On a GAAP basis, our Q3 gross margin was 55.1% compared to 67.2% in the third quarter of 2020. Our third quarter 2020 gross margin was positively impacted by a one-time license fee of $10 million from Abbott. Our non-GAAP gross margins was 54.8% in the third quarter, which is an approximate 330 basis point improvement compared to non-GAAP gross margin of 51.5% in the same quarter of last year.
Non-GAAP gross margin was 66.1% for the year-to-date 2021 period and an approximate 770 basis points improvement from non-GAAP gross margin in the same period 2020. Our non-GAAP gross margin excludes the impact of our RADx awards as well as non-cash acquisition related purchase accounting adjustments relating to our 2019 acquisition of Uman, thus providing investors with relevant period-to-period comparison of our operations. Gross margin expansion has been driven by volume, particularly in consumables, productivity gains and pricing. Our GAAP operating expenses totaled $30.5 million in the third quarter of 2021. Non-GAAP operating expenses, which primarily exclude non-recurring expenses associated with RADx grant revenue, totaled $30 million for the third quarter of 2021, an increase of $12.5 million versus non-GAAP operating expenses in the third quarter of 2020.
Major expense drivers were volume-related activity, Accelerator Laboratory expansion, expense and OSQ, the Operation Scale Quanterix expenses. During the third quarter of 2021, our cash balance decreased by $19.8 million, driven by our scaling efforts and debt repayment. Ending unrestricted cash balance was $410.7 million at September 30th, 2021, and basic weighted average shares outstanding for EPS totaled 36.5 million for the third quarter 2021 period. Overall, we're pleased with our third quarter 2021 performance and progress made on our strategic priorities and remain committed to delivering solid 2021 results in line with expectations. With that, I'll turn it back to Kevin.
Thank you very much. I appreciate that very much, Mike. You know, I wanna close before questions with slide 28 that just updates the objectives given the advances that we've had this year on so many different levels, whether it be the COVID EUAs or the p-tau 181 breakthrough designation. You can see under neurology, we actually updated this to achieve the 181, as well as to file the NfL MS breakthrough device designation. As it ends up, while this was an objective to submit it going into the year, because of COVID, we actually said that this would be delayed. We were able to actually submit the NfL MS breakthrough device designation.
This can take a year or two, particularly given that this isn't the primary area of focus, but we have in fact been able to make that at least application submission. In the area of COVID, we got the expansion of label claims for our objectives. The other piece of this we were able to achieve. The one area that we are deferring in order to accommodate what we're doing in neurology and COVID is immunology. We are slowing down some of those investments in order to stay prioritized around the increased opportunity around Aduhelm as well as donanemab, as well as even other Alzheimer's drugs that are now in trials.
Immunology will pick back up in the later years, but for the moment, we decided that it's better to stay highly focused on neurology and COVID. On the financials, the one thing we're saying here is we wanna accelerate our diagnostic investments and the 100X OpEx investments. As I stated earlier, I think getting to probably more of an OpEx around $121 million for 2021 is probably more reasonable. For next year, I think we probably will be looking to try to increase our OpEx by another 25% or somewhere probably to a level of 30% of where we were in 2021.
You know, we have an interest here to further refine this as we think through the opportunity, and we wanna make sure we stay highly preserved on cash and utilize partnerships as best we can with pharma, who have been known to give us data. We're gonna stay very efficient, but we do wanna make sure that if we see the strategic optionality around some of these trials and making sure we advance this opportunity that we now have ahead of us, that we have sufficient investment for that, and we have a very strong balance sheet to support it. Then finally on platform, you know, the hundred X, we think increasing that opportunity to get to disease even earlier is very important for the future. With that, we'll turn it over for questions.
At this time, if you would like to ask any questions, just press star one on your telephone keypad. To withdraw your question, press the pound key. We'll pause for just a moment to compile the Q&A roster. Your first question comes from the line of Kyle Mikson from Canaccord Genuity. Your line is open.
Thank you. Hi, this is Alex Vukasin on the line for Kyle Mikson. Great quarter, guys. Really impressive results. I have one quick question about your COVID offerings. More specifically, I was just curious if you had to quantify what kind of revenue you were looking at for your COVID offerings over the quarter, and I have two others after that, if that's okay.
Yep. I would say that I would not put a lot of emphasis on our COVID growth. I would say that, you know, there's kind of two comments there. There's the research side of it, where we have seen good momentum that we think is gonna be sustainable into the future because we believe infectious disease will continue to be an area that the NIH and others will be studying. We have our technology now in Anthony Fauci's lab, and have, you know, technology being analyzed, looking at different drugs for COVID into other infectious diseases. We do think that the research side of it, we have seen some nice growth, but we also believe that's gonna be sustainable into the future.
On the diagnostic side, we haven't really seen a significant advance for our own diagnostic revenues. It takes time to get established into that landscape. From our vantage point, we don't believe that diagnostic revenues for COVID are gonna be a long-term sustainable area for growth focus. We are doing everything we can to support the funding from the NIH to provide the capability and the availability for our technology, but it's not a focus of our significant go-to-market investment for the short term. We think it's important to kind of stay focused on research and then Alzheimer's for diagnostics is our primary focus.
Thank you very much. That was extremely helpful. I had one other sort of high-level question. I was just curious if you could provide an update on the competitive landscape out of what you're looking at right now, and I guess, you know, going into 2022, excuse me, as well.
Absolutely. I do think the competitive landscape is somewhat depends on the magnitude of opportunity that you're searching for and trying to influence. At the highest level, we would look at imaging as being the primary competitor to a lot of what we do with biomarkers. Meaning that today, there is an opportunity to use imaging to be able to see in the brain and to see plaque and to see the deterioration of the brain through brain atrophy in other ways. We look at what we're doing as being a much greater systemic opportunity to see much less invasively the neurology advances and pathology of the neurology advances.
Even though imaging sometimes can be looked at as competition, we think for the next five years, we look at it as being highly complementary. We think that there'll be a lot of triaging because imaging is the gold standard in many circles for neurology today. We would like to think of us as being more of an opportunity to triage and increase the scalability of what you get with imaging. You know, longer term, probably will become more competitive versus complementary. If you look also then at the diagnostic landscape, there, we're not really in there yet, right? Obviously, Roche, Abbott and Siemens are three incredibly productive companies with distributed IVD. You have Labcorp and Quest and Frontage and a lot of you know, even Mayo Clinic.
These would be companies that we actually see as partners as we are evolving. They mostly all have our technology, and they're running trials, and someday could get an LDT license from us and actually be successful providing diagnostics to patients from those laboratories. Again, some might see that as competition. Right now, we view them as being strong partners and opportunities to expand the growth of our technology much faster. We don't see them, you know, as competition. We see them as partners. Then the third way to look at this would be in the area of proteomic research. We today are sitting on what we call translational research, where we're trying to bring a lot of utility.
Once a protein gets identified as having a lot of clinical validity, we then move in with our sensitivity to reduce the invasiveness of the sample and then to increase the timing and the speed of being able to create detection. In that area of translation, we don't see a lot of competition today in these drug trials using our biomarkers. We see this as being an area that we're pioneering with not a lot of direct competition. There are some companies that we really respect a lot that are doing a lot of great work in the area of research, and they're actually identifying proteins that are leading to the longer-term pipeline. We think those companies are all very complementary, but they could someday have ambitions of moving downstream into translation.
We're always watchful for partnership opportunities, but that's also why we're fortifying our sensitivity. We believe another 100 X brings great value to the long-term translation opportunity.
Thank you very much. That's it for me.
Again, if you have any questions, just press star one on your telephone keypad. Your next question comes from the line of Matt Sykes from Goldman Sachs. Your line is open.
Hey, guys. This is Dave on for Matt. Thanks for the questions. It looks like revenue and gross margin came in strong in the quarter, but SG&A was a little heavier than what we were expecting. Could you tell us a little bit more about what went into that?
Yes, absolutely, Dave, and thanks for the question. I think that, you know, we're in a scenario where you might recall we started to build a diagnostics organization that really kicked off about four or five months ago when we brought in Masoud Toloue from PerkinElmer, who's heading up our diagnostics. He's also President of Quanterix. This is an area that we think has got a significant opportunity for the future for investors and for the growth of our company. What we've done is we've taken a lot of the advances of the COVID franchise that we created with the FDA and with payers to advance our overall capability of diagnostics.
We have a group now of about 10 individuals and that actually, if you look at our accelerator business that we ultimately see as being a laboratory developed test center, an LDT center, there's probably another 15 individuals that we've been able to pull in into this diagnostic landscape. We do think that we're now starting to make investments onto the diagnostic side, given that we've got the breakthrough device designation advances that probably have been at somewhat breakneck speed. I don't think any one of us expected Aduhelm to get approved this year, at the speed that it did and then to see the revitalization of the entire Alzheimer's, we'll call it pipeline of drug opportunities that ultimately are gonna need to get a way to get payment.
The payers were really interested in getting technologies to better diagnose and scale diagnostics for Alzheimer's, as well as to monitor, we call it, you know, kind of like evidence that the drug is performing. This whole concept of coverage with evidence, we think the payers are interested to have biomarkers monitor whether or not a drug is giving the desired performance. Because of those opportunities that became very real for us, we are investing more aggressively on that diagnostic side of our business as we're learning and building this out and surprisingly getting, you know, quicker returns with things like breakthrough designation than probably we even expected.
That's the reason why OpEx is up, and I think it's one of these things that we feel makes a lot of sense to be investing in this opportunity for longer term returns. As you know, strategic optionality, we did have three raises, all of them very productive over the last four years. These raises have put a very strong balance sheet, and we did describe the fact that there could be optionality in the area of Alzheimer's and/or diagnostics that are now coming to fruition.
Got it. That's helpful. On the p-tau breakthrough designation, any additional color you can give on how you think about the timeline with the FDA there?
Yeah. You know, I first of all would caution investors. You know, I think we probably always are taking a very cautious, you know, kind of a posture when it comes to the diagnostic landscape, particularly because it can be fraught with delays and regulatory challenges, et cetera. It's not common that you get breakthrough designation 55 days after you submit an application. So this was somewhat unprecedented. I would say that don't count on that being the pace moving forward because we know it's a delicate process of really proving the area under the curve and to further advance the utility of the actual diagnostic.
To that end, you know, I would say that we would think that it's not uncommon for it to take a couple years for a breakthrough designation to turn into a 510(k) approval. We would stay cautious, but I can tell you we're aggressively investing, and we have a lot of belief right now with the FDA, given the NIH's funding of us for COVID and being able to get the asymptomatic readings of it. You know, that's the key for us, is making sure that we don't overstate the speed in which the FDA may act. They're extremely busy right now, still working out COVID and a lot of other priorities. We did go ahead and make the submission for the NfL MS application as well.
Again, I wouldn't expect that that's gonna be fast. I do think that we are gonna work towards our own LDT approach over the next 12-18 months for p-tau 181, which would not require FDA approval, and that's something that we will be working towards from our Accelerator and through partnerships.
Got it. Helpful. Thank you.
Our pleasure.
Again, if you have any questions, just press star one on your telephone keypad. That concludes our question and answer session. I will turn the call over back to Quanterix Chairman and CEO, Mr. Kevin Hrusovsky, for closing remarks.
Thank you very much. Yes, getting a lot of kind of inbounds here that suggests that these were pretty incredible results, and we've made some massive advances strategically. You know, what I would say here is that we've got an employee base that's some of the most special people that I've ever worked with in my career, that have been working around the clock at breakneck speed throughout the pandemic and have been advancing our company on so many levels. We have a board of directors as well that's one of the best that I've seen in all of my work over the 25 years that I've been a CEO.
I'm very impressed with the team of Dawn Mattoon and, you know, Mark Roskey and just the overall breadth of the leadership that we've now been able to attract into Quanterix. We will continue working at this primarily because of the greater purpose opportunity to have a material impact on Alzheimer's over the next several years and helping see these lethal diseases earlier, less invasively. Thank you for all your support, and we look forward to talking to you at year-end results. Thank you very much.
That concludes today's conference call. Thank you for participating. You may now disconnect.