Castle Biosciences (NASDAQ:CSTL) reported fourth-quarter revenue of $87.0 million and full-year 2025 revenue of $344.2 million, supported by continued momentum in its core dermatology and gastroenterology testing franchises, management said on the company’s fourth-quarter and full-year 2025 earnings call.
Founder, President and CEO Derek Maetzold said the company’s performance reflected “continuing momentum across our core revenue drivers” and highlighted several 2025 milestones, including the acquisition of Previse, a collaboration and license agreement with SciBase, and the launch of the AdvanceAD-Tx test. CFO Frank Stokes said full-year revenue exceeded the company’s guidance range, with outperformance “driven predominantly by our core revenue drivers,” including strong growth in TissueCypher test volume.
2025 volume growth led by TissueCypher; melanoma volumes grew high single digits
- DecisionDx-Melanoma: 39,083 test reports in 2025, up 9% year over year. Maetzold said 1,795 clinicians ordered the test for the first time during 2025, with total ordering clinicians “nearing 17,000” over the life of the test. Management cited approximately 31% patient penetration exiting 2025 and noted 58 peer-reviewed publications supporting clinical use.
- TissueCypher: 39,014 test reports in 2025 versus 20,956 in 2024, representing 86% growth. Maetzold said the test has surpassed 80,000 tests ordered to date and had 2,082 new ordering clinicians in 2025, up from 1,234 in 2024. Patient penetration exiting 2025 was cited at roughly 11%.
Maetzold discussed TissueCypher’s clinical positioning in Barrett’s esophagus, noting the American Gastroenterological Association’s Barrett’s guideline highlighted TissueCypher as the first prognostic test capable of identifying Barrett’s patients at risk of progression to high-grade dysplasia or esophageal cancer.
AdvanceAD-Tx launch and pipeline initiatives
Castle’s AdvanceAD-Tx test, intended to guide systemic treatment selection for patients age 12 and older with moderate to severe atopic dermatitis, was clinically launched under a limited access model in late November 2025. Maetzold said the initial rollout was limited to about 150 dermatology accounts and that more than half of those accounts ordered at least one test in the first five weeks of clinical availability. Through mid-February 2026, the company had received “close to 500 orders,” he said.
Despite the early interest, management said revenue contribution from AdvanceAD-Tx is expected to be “immaterial in 2026,” with material revenue contribution anticipated in 2027 or 2028. Maetzold added that, based on revenue cycle timelines, the company expects to be able to communicate more about reimbursement in the second half of 2026.
Maetzold also outlined longer-term pipeline plans tied to the Previse acquisition and the SciBase collaboration:
- Non-endoscopic cell collection device (Previse): Castle plans to use the device to gather samples for development of a pipeline test for differential diagnostic and screening support for GI diseases. The company expects to enroll its first patient for a development study in the second quarter of 2026 and expects preliminary data before the end of 2026. Maetzold said the collection device requires FDA clearance and the company expects to file its submission—and potentially receive clearance—in 2026.
- SciBase EIS technology: Castle will evaluate electrical impedance spectroscopy technology, initially studying whether a handheld EIS device can predict flares in atopic dermatitis. The company expects to initiate the study and enroll its first patient in the second quarter of 2026, with preliminary development data expected before the end of 2026.
Maetzold said the company continues to view M&A as part of its strategy and described screening criteria that include tests “near or at market,” “near or at reimbursement,” compatible with sales teams “around 100 or less,” and within or complementary to existing customer verticals.
2026 outlook: revenue guidance and expense posture
Stokes provided 2026 revenue guidance of $340 million to $350 million, which he said represents “growth to mid to high teens over 2025” when excluding DecisionDx-SCC and IDgenetix revenue from both years. He added that Castle’s 2026 guide assumes immaterial revenue from AdvanceAD-Tx and includes no revenue for DecisionDx-SCC.
Gross margin in the fourth quarter was 76.3%, essentially flat year over year. Full-year 2025 gross margin was 69.2%, down from 78.5% in 2024, which Stokes said was affected by the loss of DecisionDx-SCC revenue and a one-time acceleration of amortization expense of approximately $20.1 million in the first quarter of 2025. Adjusted gross margin was 77.6% for the quarter and 79.8% for the year.
Total operating expenses, including cost of sales, were $90.8 million in the fourth quarter and $387.0 million for the full year, up from $323.4 million in 2024. Stokes said the company expects operating expenses to increase “moderately” in 2026 as it invests in core franchises, advances the pipeline, and supports reimbursement and commercial initiatives.
Profitability, cash flow and balance sheet
Castle reported a fourth-quarter 2025 net loss of $2.3 million, compared with net income of $9.6 million a year earlier. Full-year 2025 net loss was $24.2 million versus net income of $18.2 million in 2024. Adjusted EBITDA was $11.5 million for the fourth quarter and $44.0 million for the full year, down from $21.3 million and $75.0 million, respectively, in 2024.
Net cash provided by operating activities was $26.9 million in the fourth quarter and $64.3 million for the full year. Capital expenditures totaled $36.0 million in 2025, and Stokes said capital expenditures are expected to decline in 2026. As of December 31, 2025, Castle had $299.5 million in cash, cash equivalents and marketable securities.
Guidelines, FDA plans, and commercial execution themes raised in Q&A
During the question-and-answer session, management discussed recent NCCN guideline updates related to DecisionDx-Melanoma and reiterated the long-standing 5% threshold used in considerations around sentinel lymph node biopsy. Maetzold said Castle data has repeatedly shown that a low-risk DecisionDx-Melanoma result can place patients “comfortably below 5%.” He also said only 11 of 58 peer-reviewed publications supporting the test were cited in current guidelines, calling it “a bit of a head-scratcher.”
Maetzold said Castle is preparing an FDA submission for DecisionDx-Melanoma and expects it to be accepted as a de novo 510(k) rather than a PMA. He said clearance could occur toward the end of 2026 or early 2027, though timing is uncertain. He added the main rationale for pursuing clearance is to leverage state biomarker laws that may support reimbursement when a test is FDA-cleared or approved, with the goal of reducing non-payments from commercial insurers and improving average selling price.
On 2026 volume expectations, Stokes said Castle anticipates “mid to high single digits” DecisionDx-Melanoma volume growth. On TissueCypher, management said it expects continued strong growth, though it cautioned that percentage growth may moderate as volumes increase and adoption extends into later adopters.
Management also described sales force planning and limited access controls for AdvanceAD-Tx, including maintaining continued focus on melanoma while gradually shifting incentives as the company expands access and tracks operational readiness and ASP performance.
About Castle Biosciences (NASDAQ:CSTL)
Castle Biosciences, Inc is a molecular diagnostics company specializing in the development and commercialization of prognostic and diagnostic tests for patients with dermatologic conditions. The company’s proprietary portfolio of genomic assays is designed to improve risk assessment and guide clinical decision-making for individuals with skin cancers and other skin-related diseases. By combining genomic data with advanced statistical algorithms, Castle Biosciences seeks to provide actionable insights that help physicians tailor treatment plans and monitoring strategies.
The company’s flagship test, DecisionDx-Melanoma, evaluates the probability of metastasis in patients diagnosed with cutaneous melanoma, supporting more personalized surveillance and therapeutic approaches.
