Castle Biosciences Confirms Pivot: TissueCypher and AdvanceAD Drive Guidance Raise

Q2 revenue up 20% (40% ex-SCC), guidance raised 17% at midpoint, and AdvanceAD-Tx secures a crosswalk rate—signaling a strategic shift beyond melanoma.

CSTL · Earnings Call · 2026-07-30

A Blowout Quarter, Led by the Core

Castle Biosciences delivered a standout Q2, with revenue of $103.5 million—20% growth year-over-year—and, critically, “if we exclude DecisionDx-SCC and IDgenetix revenue for both 2026 and 2025, our revenue growth for the second quarter of 2026 was 40%” — Derek Maetzold, Founder, President and Chief Executive Officer · 2026-07-30. This underscores that the core franchise—sentinel lymph node testing via DecisionDx-Melanoma and the fast-scaling TissueCypher test—is accelerating even as the legacy SCC business winds down. Management raised full-year 2026 revenue guidance to $365–375 million from $345–355 million, a $20 million step at the midpoint, largely banked on current momentum. The stock has responded forcefully: CSTL is up ~48% over the last 90 days, and the recent 90-day trend shows a decisive up-leg after a period of consolidation. The market is recognizing that this is no longer just a one-product dermatology story.

The AdvanceAD-Tx Crosswalk: A Strategic Pivot

The most significant strategic development is the unanimous panel vote to crosswalk AdvanceAD-Tx to a code with a reimbursement rate of $3,675. As Derek Maetzold noted, “The rate of [ $3,675 ], I think, is a very, very strong rate for our test.” — Derek Maetzold, Founder, President and Chief Executive Officer · 2026-07-30 This provides a CMS benchmark that can anchor commercial payer negotiations, a crucial step for a test that predicts systemic drug response in atopic dermatitis—a completely new therapeutic area for Castle.

Obviously, the panel did 2, I think it was a 21 to 0 vote in favor of crosswalking. The rate of [ $3,675 ], I think, is a very, very strong rate for our test.
Derek Maetzold, Founder, President and Chief Executive Officer · 2026-07-30

This is a deliberate shift from the company's historical focus on melanoma. In the prior quarter call, management talked about a limited launch and “we opened up access a bit more late in the first quarter” — Derek J. Maetzold, Founder, President, and Chief Executive Officer · 2026-05-06 (from the Q2 2026 call), but now they are preparing to scale. The AdvanceAD-Tx provided more than 1,000 orders in Q2 alone, and with a clear reimbursement path, the company expects to broaden commercial launch into 2027. This is a company-unique pivot that opens a large addressable market of 13.2 million patients with moderate-to-severe atopic dermatitis.

TissueCypher's Runway and the New Seasonality

TissueCypher remains the growth engine, with volumes up 63% year-over-year. Management now guides to 50–52% volume growth for the full year, and crucially, they are beginning to see seasonality—a sign the test has reached a penetration level where the patient-flow cadence matters. Frank Stokes explained, “Yes, we did have some pickup in ASP, Max. ... I would not expect to see the same stepwise increase in the back half.” — Frank Stokes, Chief Financial Officer · 2026-07-30 That ASP improvement was partly a one-time benefit from updated accrual processes, but it highlights the revenue leverage in the model. The Total Revenue trajectory confirms the compound growth: the 2-year trend shows +327% growth, and even with the SCC wind-down, the company posted $103.5M in the quarter—well above the $84M in Q1. The gross margin dipped to 74.9% (adjusted 76.3%) due to mix, but management expects adjusted gross margin to stay in the low-to-mid 70s, still strong for the sector. Importantly, the company is now guiding to positive adjusted EBITDA for Q3, Q4, and the full year 2026, and for 2027 absent any strategic shifts. That's a major milestone—casting aside the prior concern about cash burn. The balance sheet is robust, with $266.8M in cash and marketable securities, supporting continued R&D investment.

What It Means

Castle Biosciences is no longer a single-test story. The convergence of a durable TissueCypher franchise, a new high-reimbursement ADTx test, and a clear path to profitability creates a multi-product, multi-indication thesis. The prior quarter's discussion of FDA submission for melanoma (“We are preparing our submission as we speak now.” — Derek Maetzold, Founder, President and Chief Executive Officer · 2026-02-26) remains on track, potentially unlocking state biomarker laws and improving commercial ASPs. The market has rewarded the stock with a 48% rally over 90 days, and the guidance raise validates the inflection. The key question now is execution: scaling the commercial launch of AdvanceAD-Tx without diluting the focus on the core melanoma franchise, which already has impressive depth (58 peer-reviewed publications). If the company can sustain mid-40% core growth while transitioning to profitability, the re-rating is justified. The crosswalk was the missing catalyst, and now it's in hand.