In summary, we continue to make great progress in our target and drug discovery programs in cancer and autoimmunity. Our immune medicine business remains laser focused to execute on additional key R&D and future clinical proof points that drive meaningful value inflections. For our partners and wholly-owned drug discovery pipeline. With that, I’ll now pass it over to Tycho. Tycho Peterson Thanks, Chad. Turning to our financials on Slide 7, total revenue in the third quarter was $37.9 million with 65% from MRD and 35% from Immune Medicine representing a 21% decline from the same period last year. The MRD business overall has been strong, driven by high volume growth of clonoSEQ. The total revenue declined in 3Q was primarily driven by a 61% reduction in Genentech amortization and a 14% decrease in MRD Pharma and Immune Medicine Pharma Services due to the biopharma headwinds that we previously discussed, partially offset by strong clonoSEQ clinical performance.
MRD revenue grew 24% from a year ago to $24.7 million. clonoSEQ clinical was the main driver with test volume, including international increasing 56% to 15,072 tests delivered from 9,649 tests in the same period last year. MRD Pharma declined 4% and no milestones were recognized in the quarter. Immune Medicine revenue was $13.3 million, down 52% from a year ago with lower Genentech amortization driving 85% of the decline. Immune Medicine Pharma Services, which saw 29% decline versus the prior year also experienced downward pressure from biopharma. Moving down to P&L on Slide 8. Total gross margin for the quarter was 49%. The decline in gross margin versus the prior year was largely attributable to lower amortization of the Genentech upfront, which has 100% margin contribution and incremental one-time costs from the lab moves.
Versus the second quarter, the decline was mainly driven by no milestones compared to the Genentech milestone we realized last quarter in addition to product mix tied to reduced pharma services and incremental costs from completion of the lab move. We continued to focus on optimizing operations to further enhance margins. This includes the implementation of a new LIMS ecosystem by mid-2024, which will allow us to reduce overhead and increase the productivity of direct labor in the lab. In addition, after completing a technical feasibility review, we will be switching from m NextSeq to NovaSeq sequencers next year. We expect completion by late 2024, bring significant savings and material costs in 2025. Importantly, other OpEx, excluding cost of revenue declined 11% versus the prior year and 12% versus the prior quarter as we continue to be laser-focused in driving operating leverage and efficiencies across the organization.
Interest expense from our royalty financing agreement with OrbiMed $3.7 million, which was offset by interest and other income of $4.3 million. Net loss for the quarter was $50.3 million, compared to $45.3 million last year. We ended the quarter with approximately $371 million in cash, equivalents and marketable securities. Now, turning to updated guidance on Slide 9. As Chad mentioned, given the ongoing strategic review, we are updating total company revenue guidance for 2023 to exclude Immune Medicine revenue. Going forward Immune Medicine will resemble a more traditional drug discovery biotech model and we want to ensure that we do not trade-off short-term revenues for long-term value and accordingly, we will not be providing revenue guidance for that business going forward.
For MRD, we continue to expect clonoSEQ test volumes to grow over 50% for the full year versus 2022. ASPs in the fourth quarter are expected to grow mid-single-digits sequentially. We expect pharma services to continue experiencing downward pressure from biopharma industry spending in the fourth quarter and MRD milestones are expected to be in the low-single-digits. Putting it together, we expect total MRD revenue for 2023 to be in the range of $100 million to $105 million. As we continue to drive operating efficiencies, our total company full year OpEx target, including cost of revenue, is expected to be around $375 million, a decrease of approximately 3% from last year. Cash flow for the third quarter was $46 million, and higher than anticipated due to the lower pharma service revenues, but we expect the 4Q burn to be more normalized at around $35 million.
Q3 had important achievements in both businesses, and we remain focused on driving execution, while managing our spending prudently, as we closed the year and complete the strategic review. I’ll now turn the call back over to Chad.
Chad Robins: Thanks. Tycho. I am confident in the potential value of MRD and Immune Medicine, and we look forward to arriving in an optimal outcome that maximizes each business to best serve our patients, and our shareholders. With that, I’d like to turn the call back over the operator and open up for questions. Question-And-Answer Session Operator Thank you. [Operator Instructions] And our first question today comes from the line of Mark Massaro with BTIG. Mark, please go ahead.
Mark Massaro : Hey guys. Thank you for the time and the questions. The first one is just, I guess, why now? I think there’s been some discussion about synergies or lack thereof of the two businesses, just curious, why you’re conducting this formal strategic review at this time? And maybe just any comments you have about the two businesses and should we read into this that there are just not parallel synergies between the two?
