Artistic rendering of HER2 IHC staining showing membrane positivity pattern in breast tissue

HER2 Scoring

Automated HER2 Scoring per ASCO/CAP Guidelines

0 to 3+ classification with equivocal case flagging for ISH reflex. Membrane staining intensity quantified at cell-level resolution.

EXAMPLE OUTPUT

HER2_result = {
  "classification": "2+ (Equivocal)",
  "h_score": 94,
  "pct_3plus": 8.2,
  "pct_2plus": 31.7,
  "ish_flag": true,
  "confidence": "High"
}

Scoring System

HER2 0 / 1+ / 2+ / 3+ Classification

Per 2018 ASCO/CAP HER2 Testing Guidelines for breast carcinoma.

Score Pattern Description Synthia Measurement Clinical Interpretation
0 No staining or incomplete faint membranous staining in ≤10% of invasive tumor cells H-score < 10; <10% cells show any membrane staining HER2 negative — no targeted therapy indication
1+ Incomplete faint/barely perceptible membranous staining; staining in >10% of invasive tumor cells Incomplete/weak membrane signal; H-score 10–54 HER2 negative — no targeted therapy indication
2+ Circumferential incomplete and/or weak-to-moderate complete membranous staining in >10% of invasive tumor cells Moderate membrane intensity or incomplete complete staining; H-score 55–179; ISH flag triggered HER2 equivocal — reflex ISH testing required per ASCO/CAP
3+ Circumferential complete and intense membranous staining in >10% of invasive tumor cells Strong complete circumferential membrane staining; H-score ≥180; ≥10% cells 3+ intensity HER2 positive — trastuzumab/pertuzumab therapy eligible

How Synthia Determines Each Grade

Synthia segments each cell nucleus and maps membrane-associated DAB staining to classify staining as complete circumferential (3+), incomplete or weak circumferential (2+/1+), or absent (0). Staining intensity is quantified on a continuous scale using calibrated optical density thresholds derived from pathologist-annotated reference cases.

For 2+ equivocal cases, the system generates both the primary IHC classification and an automated ISH reflex recommendation note — reducing the need for pathologists to remember guideline thresholds for borderline cases.

The output is a full structured report including: overall H-score, percentage of cells at each staining intensity level, spatial heatmap overlay, and the ASCO/CAP classification with confidence interval.

HER2 Classification Detail
HER2 class 2+ Equivocal
H-score (0–300) 94
Cells 3+ intensity 8.2%
Cells 2+ intensity 31.7%
Cells 1+ intensity 28.4%
Cells 0 intensity 31.7%
ISH reflex flag RECOMMENDED

Performance Metrics

HER2 Internal Validation Results

Internal study, data on file. For investigational use only. Performance in your laboratory may vary.

HER2
Concordance vs. 3-Pathologist Consensus
Internal validation · n=380 WSI · breast carcinoma biopsies
Metric Value 95% CI Reference Standard
Overall concordance (0/1+/2+/3+) 91.8% 89.2–94.1% 3-reader majority vote
Weighted Kappa 0.89 0.86–0.92 Linear weight
ICC (continuous H-score) 0.94 0.92–0.96 Pathologist H-score estimate
Equivocal 2+ rate 18.4% — Per ASCO/CAP expected range
Equivocal concordance with consensus 88.6% 83.4–92.8% 2+ identification agreement
Test-retest ICC (n=50) 0.997 0.995–0.999 Same slide, 7-day interval
Disclaimer: Internal validation studies. Data on file. Synthia is not FDA cleared or approved. For research and investigational use only. Performance in your laboratory environment may differ from internal validation results.

Test HER2 Scoring on Your Slides

Submit a de-identified HER2 breast cancer WSI set for a pilot report. Receive scored results and a concordance breakdown within 48 hours.

Request Pilot Access Full Validation Data