CSTL
HealthcareCastle Biosciences, Inc. · Medical - Diagnostics & Research · $610M
What is Castle Biosciences, Inc.?
Castle Biosciences is a commercial-stage diagnostics company focused on genetic testing for dermatological cancers. Based in Friendswood, Texas, it serves physicians and patients who need clearer prognostic information at the point of diagnosis.
Castle Biosciences develops and delivers gene expression profile tests that help clinicians assess the risk of cancer metastasis in individual patients. Rather than relying on traditional staging alone, its tests analyze tumor biology at the molecular level to guide treatment decisions. The company generates revenue by providing these laboratory services through ordering physicians, with tests covering melanoma, squamous cell carcinoma, and related dermatological conditions.
Castle Biosciences was founded in 2007 and is headquartered in Friendswood, Texas.
- DecisionDx-Melanoma: metastasis risk test for invasive cutaneous melanoma
- DecisionDx-UM: prognostic test for uveal melanoma, a rare eye cancer
- DecisionDx-SCC: 40-gene test predicting squamous cell carcinoma metastasis risk
- DecisionDx DiffDx-Melanoma and myPath Melanoma: diagnostic tests for suspicious pigmented lesions
Is CSTL a Good Stock to Buy?
UQS Score rates CSTL as Below Average overall.
The standout pillar for Castle Biosciences is Risk, which scores Strong — suggesting the company's financial risk profile is relatively contained for a small-cap diagnostics name. This may reflect a manageable balance sheet or limited near-term liquidity concerns relative to peers.
Quality, Moat, and Growth all register as Weak, pointing to challenges in profitability, competitive differentiation, and revenue expansion. Valuation is rated Elevated, meaning the current price may not offer a wide margin of safety given those underlying fundamentals.
Pro members can see the exact pillar breakdown and the full financial metrics behind each score — sign up at uqs-score.com. Sign up free →
Past performance does not guarantee future results. UQS Score is based on fundamental data and is not a buy/sell recommendation.
Does CSTL pay dividends?
No — Castle Biosciences, Inc. does not currently pay a dividend.
Castle Biosciences does not currently pay a dividend. As a commercial-stage diagnostics company still working toward consistent profitability, available capital is directed toward expanding test adoption, building clinical evidence, and growing its sales infrastructure rather than returning cash to shareholders.
When does CSTL report earnings?
Castle Biosciences reports earnings on a quarterly cadence, consistent with standard practice for US-listed equities.
The company's recent results reflect the dynamics of a diagnostics business scaling its test volumes while managing operating costs. Revenue growth has been tied to physician adoption of its gene expression profile tests, though profitability remains a work in progress.
For the most recent quarter's results and guidance commentary, visit Castle Biosciences' investor relations page directly.
CSTL Price History
-59.0% over 5Y
Monthly close, adjusted for stock splits and dividend reinvestment.
CSTL Long-term Outlook
The UQS Growth pillar for CSTL is rated Weak, indicating that near-term expansion may be constrained by the pace of clinical adoption and reimbursement coverage decisions. The Strong Risk rating provides some reassurance that the company is not in immediate financial distress, but the Weak Moat and Elevated Valuation create a challenging combination for long-term return potential. Investors should weigh whether the company's niche in dermatological diagnostics can translate into durable revenue growth before the current valuation becomes more justified.
Growth drivers
- Broader physician adoption of gene expression profile tests in oncology workflows
- Potential expansion into additional cancer types or new diagnostic indications
- Reimbursement coverage gains that reduce barriers to test ordering
Key risks
- Weak moat leaves the company exposed to competing diagnostic platforms from larger players
- Elevated valuation limits the buffer if growth targets are missed
- Reimbursement and coverage decisions by payers remain a key variable for revenue visibility
CSTL vs Peers
Castle Biosciences operates in a competitive diagnostics landscape alongside several other specialty and genomic testing companies.
Personalis focuses on whole-genome sequencing for oncology, targeting broader cancer genomics rather than Castle's dermatology-specific gene expression tests.
OPKO Health operates across diagnostics and pharmaceuticals with a broader product portfolio, contrasting with Castle's concentrated focus on skin cancer testing.
Aclaris is a dermatology-focused biopharmaceutical company developing drug therapies, occupying a different part of the dermatology value chain than Castle's diagnostic testing model.
Frequently Asked Questions
What does Castle Biosciences do?
Castle Biosciences develops gene expression profile tests that help doctors assess the risk of cancer spreading in individual patients. Its tests are focused on dermatological cancers, including melanoma and squamous cell carcinoma, and are ordered by physicians to inform treatment planning.
Does CSTL pay dividends?
No, Castle Biosciences does not currently pay a dividend. The company is in a commercial growth phase and reinvests available capital into expanding its testing platform and clinical evidence base rather than distributing cash to shareholders.
When does CSTL report earnings?
Castle Biosciences follows a standard quarterly earnings schedule. For the exact dates of upcoming reports and access to past results, check the investor relations section of the company's official website.
Is CSTL a good stock to buy?
The UQS Score rates CSTL as Below Average, reflecting Weak readings across Quality, Moat, and Growth pillars alongside an Elevated Valuation. The Risk pillar is Strong, which is a relative positive. Whether this profile suits your investment approach depends on your tolerance for early-stage diagnostics risk — view the full breakdown at uqs-score.com.
Is CSTL overvalued?
The UQS Valuation pillar for CSTL is rated Elevated, suggesting the stock may be priced richly relative to its current fundamental profile. When combined with Weak Quality and Growth scores, the valuation leaves limited room for error. Pro members can see the specific valuation metrics behind this rating.
How does CSTL compare to its competitors?
Compared to peers like Personalis and OPKO Health, Castle Biosciences occupies a narrower niche — dermatological cancer diagnostics using proprietary gene expression tests. This focus can be a strength in clinical credibility but also limits diversification relative to broader diagnostics or genomics platforms.
What is CSTL's market cap bracket?
Castle Biosciences is classified as a small-cap company. This places it in a category where liquidity, analyst coverage, and access to capital can be more limited than for large- or mega-cap peers, which is a relevant consideration for risk assessment.
Who founded Castle Biosciences?
Castle Biosciences was founded in 2007. For details on the founding team and leadership history, the company's official website and public filings provide accurate and up-to-date information.
Is CSTL a long-term quality investment?
As a long-term quality indicator, the UQS Score rates CSTL as Below Average. The Weak Moat and Quality pillars suggest the company has not yet established the durable competitive advantages typically associated with high-quality long-term holdings. The Strong Risk score is a constructive sign, but the overall profile warrants careful evaluation.
What is the main competitive advantage of Castle Biosciences?
Castle Biosciences' primary differentiation lies in its proprietary gene expression profile tests, which are built on clinical evidence developed specifically for dermatological cancer patients. However, the UQS Moat pillar rates this advantage as Weak, indicating that competitive barriers may not yet be deeply entrenched.
What sector does CSTL belong to?
Castle Biosciences operates in the Healthcare sector, specifically within the diagnostics and genomic testing segment. It serves the dermatological oncology market, providing molecular testing services to physicians treating skin cancer patients.
Is CSTL a growth stock or value stock?
Based on UQS pillar labels, CSTL carries a Weak Growth rating and an Elevated Valuation — a combination that fits neither the classic growth nor value profile cleanly. It is a commercial-stage diagnostics company where growth execution and valuation alignment remain key open questions.
Unlock Full CSTL Analysis
Sign in to unlock the detailed analysis behind the UQS Score.
- ✓See the exact UQS Score and all five pillar ratings
- ✓View full financial metrics behind each pillar
- ✓Compare CSTL against sector peers side by side
- ✓Access the complete analyst-style quality breakdown
- ✓Track score changes as new data is published
- ✓Screen for stronger-rated healthcare diagnostics stocks
Pro Analysis
CSTL — Score History
| Date | UQS | Quality | Moat | Growth | Risk | Value | Change |
|---|---|---|---|---|---|---|---|
| May 23, 2026 | 38.7 | 18.2 | 30.0 | 38.2 | 47.1 | 79.3 | +0.1 |
| May 22, 2026 | 38.6 | 18.2 | 30.0 | 38.2 | 47.1 | 78.7 | -0.1 |
| May 21, 2026 | 38.7 | 18.2 | 30.0 | 38.2 | 47.1 | 79.3 | -0.3 |
| May 20, 2026 | 39.0 | 18.2 | 30.0 | 38.2 | 47.1 | 81.3 | +0.1 |
| May 19, 2026 | 38.9 | 18.2 | 30.0 | 38.2 | 47.1 | 80.7 | -0.1 |
| May 16, 2026 | 39.0 | 18.2 | 30.0 | 38.2 | 47.1 | 81.3 | -0.1 |
| May 15, 2026 | 39.1 | 18.2 | 30.0 | 38.2 | 47.1 | 82.0 | -0.1 |
| May 14, 2026 | 39.2 | 18.2 | 30.0 | 38.1 | 47.1 | 83.3 | +0.2 |
| May 13, 2026 | 39.0 | 18.2 | 30.0 | 38.1 | 47.1 | 82.0 | +0.1 |
| May 12, 2026 | 38.9 | 18.2 | 30.0 | 38.1 | 47.1 | 81.3 | +0.2 |
CSTL — Pillar Breakdown
Quality
— 18.2/100 (25%)Castle Biosciences, Inc. currently shows below-average quality metrics, suggesting challenges with profitability.
How effectively capital is deployed to generate returns.
Profitability relative to shareholders' equity.
Ability to convert revenue into operating profit.
Bottom-line profit as a share of revenue.
Asset productivity — how much gross profit each dollar of assets generates.
Free cash flow relative to market value.
Growth
— 38.2/100 (20%)Castle Biosciences, Inc. shows steady but unspectacular growth, typical for mature companies.
Revenue trajectory over the last twelve months.
Compound annual revenue growth rate over 3 years.
Year-over-year earnings per share growth.
Analyst consensus for future revenue growth.
Risk
— 47.1/100 (15%)Castle Biosciences, Inc. has some risk factors including moderate leverage or solvency concerns.
Debt levels relative to earnings capacity.
Total debt relative to shareholder equity.
Short-term liquidity — ability to pay near-term obligations.
Earnings capacity relative to interest payments.
Valuation
— 79.3/100 (15%)Castle Biosciences, Inc. appears attractively valued relative to its earnings, cash flows, and sector peers.
How many years of FCF the market cap represents.
Moat
— 30/100 (25%)Castle Biosciences, Inc. operates in a highly competitive environment with limited sustainable advantages. The Moat pillar evaluates competitive advantages across five dimensions: Switching Costs, Network Effects, Cost Advantage, Intangible Assets, and Scale & Ecosystem. Sign in to customize moat ratings for CSTL.
Score Composition
Financial Data
More Stock Analysis
How is the CSTL UQS Score Calculated?
The UQS (Unified Quality Score) for Castle Biosciences, Inc. is calculated using a proprietary 6-pillar framework with 29 financial metrics. Each pillar evaluates a different dimension on a 0–100 scale, then combines into a single weighted score. Scoring thresholds are calibrated per sector. Momentum is an optional Pro toggle — without it, you get the 5-pillar / 25-metric core shown below.
Quality (25%) measures profitability and capital efficiency — ROIC, ROE, margins, GP/Assets, and FCF Yield.
Moat (25%) assesses Castle Biosciences, Inc.'s competitive advantages across switching costs, network effects, cost advantages, intangible assets, and ecosystem scale.
Growth (20%) tracks revenue trajectory and earnings momentum, combining historical results with analyst forward estimates.
Risk (15%) is inversely scored — lower leverage and strong balance sheet health result in higher scores.
Valuation (15%) measures whether Castle Biosciences, Inc. is fairly priced using earnings yield, price-to-FCF, PEG ratio, and EV/EBITDA relative to sector peers.
Six investor-inspired presets are available, each with different pillar weights: Balanced, Buffett, Munger, Lynch, Cathie Wood, and Graham. The public score shown here uses the Balanced preset. Learn more in our FAQ.