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CSTLCastle Biosciences, Inc.Sell5.1·$23.64-0.80%
SellModerate Confidence
Investment thesis

Castle Biosciences shows a perfect recent earnings-beat streak and steep analyst-implied upside, with technicals reading as a pullback rather than a breakdown, but a sub-floor quality score, a failing Rule of 40 metric, and notable insider selling keep the engine's stance at exit.

Thesis pillars

  • Analyst Upside ValuationStable
  • Earnings Beat StreakStable
  • Momentum Pullback Not BreakdownStable
  • +2 more pillars — see the Why tab for full reasoning

Full reasoning →

Open full analysis

Castle Biosciences, Inc. (CSTL) Stock Analysis

Catalyst-Driven edge

SellShortModerate Confidence

Healthcare · Diagnostics & Research

Sell if holding. Engine safety override at $23.64: Quality below floor (3.5 < 4.0) triggers a hard block regardless of the otherwise-positive setup — overall score 5.1/10 and A.R:R 4.0:1 is above the 1.5:1 BUY gate. Specifically: Elevated put/call ratio: 2.20; Below-average business quality; Below long-term trend.

Castle Biosciences is a molecular diagnostics company selling gene-expression profile and spatialomics tests — including DecisionDx-Melanoma, TissueCypher, DecisionDx-SCC, MyPath Melanoma, and DecisionDx-UM — that guide treatment decisions in dermatologic cancers, Barrett's... Read more

$23.64+60.3% A.UpsideScore 5.1/10#23 of 32 Diagnostics & Research
QualityF-score6 / 9FCF yield1.76%
Stop $21.99Target $37.89(analyst − 13%)A.R:R 4.0:1
Analyst target$43.56+84.2%9 analysts
$37.89our TP
$23.64price
$43.56mean
$52

Sell if holding. Engine safety override at $23.64: Quality below floor (3.5 < 4.0) triggers a hard block regardless of the otherwise-positive setup — overall score 5.1/10 and A.R:R 4.0:1 is above the 1.5:1 BUY gate. Specifically: Elevated put/call ratio: 2.20; Below-average business quality; Below long-term trend. Chart setup: No clear chart pattern; technical signals are mixed. Score 5.1/10, moderate confidence.

Passes 8/9 gates (positive momentum, favorable risk/reward ratio, clean insider activity, no SEC red flags, news events none recent, earnings proximity 27d clear, semi cycle peak clear, materials cycle peak clear). Suitability: speculative.

10-K grounded · weekly refresh

About Castle Biosciences, Inc.

About Castle Biosciences, Inc.

Castle Biosciences delivered 105,053 diagnostic test reports across its dermatology, gastroenterology, and ophthalmology portfolio in 2025, up from 96,071 in 2024, driving net revenues of $344.2 million for the year ended December 31, 2025 versus $332.1 million in 2024. The molecular diagnostics company runs its DecisionDx-Melanoma, TissueCypher, DecisionDx-SCC, MyPath Melanoma, and DecisionDx-UM tests from labs in Phoenix, Arizona and Pittsburgh, Pennsylvania.

Castle Biosciences earns revenue by billing government and commercial third-party payors for each test report, with reimbursement rates set under Medicare's Advanced Diagnostic Laboratory Test framework — $7,193 per DecisionDx-Melanoma test, $4,950 per TissueCypher test, and $7,776 per DecisionDx-UM test for 2026. TissueCypher led 2025 volume growth at 39,014 reports, up from 20,956 in 2024, while the company discontinued its IDgenetix pharmacogenomic test in May 2025 and began a limited launch of the AdvanceAD-Tx atopic-dermatitis test that November. The company expanded its Barrett's esophagus franchise in 2025 through the acquisition of Previse, adding methylation-based intellectual property and a non-endoscopic cell-collection device expected to support a supplemental Esopredict test in 2026, and separately licensed SciBase's Electrical Impedance Spectroscopy technology for North American dermatology diagnostics.

Show full overview

Medicare supplied 44% of Castle Biosciences' revenue in 2025 and a single unnamed commercial payor contributed another 16%, concentrating close to two-thirds of revenue in two payor relationships. That dependence is sharpened by DecisionDx-SCC's Medicare coverage loss: Medicare contractor Novitas finalized a non-coverage local coverage determination effective April 24, 2025 after a multi-year review process, and while Castle submitted reconsideration requests to both Novitas and the Palmetto MolDX program in July 2025, confirmation that a request is valid does not indicate a favorable outcome is coming.

See also: Healthcare · Diagnostics & Research

From Castle Biosciences, Inc.'s most recent 10-K filing, extracted July 6, 2026.

TrendMatrix Research · upcoming catalyst calendar

Upcoming dated catalysts

Mon, Aug 3, 202627d to earnings· next earnings call

Thesis

Rewards
No bull case signals
Risks
Quality below floor (3.5 < 4.0)

Key Metrics

P/E (TTM)
P/E (Fwd)-25.9
Mkt Cap$734M
EV/EBITDA-27.8
Profit Mgn-3.8%
ROE-2.8%
Rev Growth-4.9%
Beta1.00
DividendNone
Rating analysts15

Quality Signals

Piotroski F6/9MoatNarrow

Options Flow

P/C2.20bearish
IV77%elevated

Concentration Risks(10-K Item 1A)

  • MEDIUMCustomerMedicare44%
    10-K Item 1: 'Our revenue from patients covered by Medicare as a percentage of total revenue, was 44% for the year ended December 31, 2025.'
  • LOWCustomersingle commercial payor16%
    10-K Item 1: 'there was a commercial payor from which 16% of our revenue from patients was derived for the year ended December 31, 2025.'

Model-generated analysis — not investment advice. Not a registered investment advisor. Past performance does not guarantee future results.

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Performance. Past performance is not indicative of future results. Performance figures reflect the published model only and do not reflect any individual subscriber's actual results.

Methodology · Editorial policy & full disclaimer

Rating Breakdown

3 floor-breakers·1 ceiling hit

Revenue shrinking — -4.9% YoY. Growth thesis broken unless recovery story develops.static

Revenue Growth
1.3
Declining revenue: -5%
Low model confidence on this dimension (33%).

Technicals below the gate floor. Component breakdown shows what dragged the score down.static

52w Position
0.7
Support Resistance
2.6
Bollinger
3.0
Gap
6.0

Unprofitable operations — net margin -3.8%. Quality floor flags this regardless of sector context.static

Roe
0.0
Roa
0.0
Operating Margin
0.0
Net Margin
0.0
Rule Of 40
3.0
Fcf Quality
3.8
Moat
5.5
Current Ratio
6.3
Piotroski F
6.7
Gross Margin
10.0
FCF-positive despite GAAP loss (FCF margin 4%, FCF yield 1.8%)Rule of 40: -1 (fail)
GatesMomentum 5.1<5.5 (soft — BUY_NOW allowed but watch)Momentum 5.1>=4.5A.R:R 4.0 ≥ 1.5Insider activity: OKNo SEC red flagsNEWS EVENTS NONE RECENTEARNINGS PROXIMITY 27d clearSEMI CYCLE PEAK CLEARMATERIALS CYCLE PEAK CLEARSuitability: Speculative
RSI
73 · Overbought
20D MA 50D MA 200D MADEATH CROSSSupport $19.86Resistance $24.98

Price Targets

$22
$38
A.Upside+60.3%
A.R:R4.0:1

Position Sizing

ConvictionNone
Suggested %0.5%
Max %1%
RegimeSteady

Risk Alerts

! Quality below floor (3.5 < 4.0)

Earnings

B
B
B
M
3/4 beats
Next Earnings2026-08-03 (27d)

Verdict History

reverse chrono — latest first
Loading history...
Verdicts are recorded on every nightly pipeline run. Rows capture transitions (verdict flips, score deltas ≥0.3, entry/TP/SL changes). Rows with a ▶ can be expanded to see the change reason. Aggregate cohort performance is tracked in the recommendation ledger.
Frequently Asked Questions
Is CSTL stock a buy right now?

Sell if holding. Engine safety override at $23.64: Quality below floor (3.5 < 4.0) triggers a hard block regardless of the otherwise-positive setup — overall score 5.1/10 and A.R:R 4.0:1 is above the 1.5:1 BUY gate. Specifically: Elevated put/call ratio: 2.20; Below-average business quality; Below long-term trend. Chart setup: No clear chart pattern; technical signals are mixed. Prior stop was $21.99. Score 5.1/10, moderate confidence.

What is the CSTL stock price target?

Take-profit target: $37.89 (+60.3% upside). Prior stop was $21.99. Stop-loss: $21.99.

What are the risks of investing in CSTL?

Quality below floor (3.5 < 4.0).

Is CSTL overvalued or undervalued?

Castle Biosciences, Inc. trades at a P/E of N/A (forward -25.9). TrendMatrix value score: 9.0/10. Verdict: Sell.

What do analysts say about CSTL?

15 analysts cover CSTL with a consensus score of 4.4/5. Average price target: $44.

What does Castle Biosciences, Inc. do?Castle Biosciences is a molecular diagnostics company selling gene-expression profile and spatialomics tests —...

Castle Biosciences is a molecular diagnostics company selling gene-expression profile and spatialomics tests — including DecisionDx-Melanoma, TissueCypher, DecisionDx-SCC, MyPath Melanoma, and DecisionDx-UM — that guide treatment decisions in dermatologic cancers, Barrett's esophagus, and atopic dermatitis. The company delivered 105,053 test reports and generated $344.2 million in net revenue in 2025, with Medicare accounting for 44% of revenue and a single commercial payor contributing 16%.

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