Galleri®'s clinical evidence base comes from three major programs: CCGA (case-control), PATHFINDER 1-2 (prospective) and NHS-Galleri (randomized controlled trial). This article compiles the performance metrics and cohorts.
Performance Metrics (CCGA3)
| Metric | Value | Source |
|---|---|---|
| Specificity | 99.5–99.85% | CCGA3 (all cancers) |
| Positive predictive value | 66–77% | CCGA3 |
| Sensitivity — all cancers | 51.5% | CCGA3 |
| Sensitivity — 12 deadly cancers | 76.3% | CCGA3 |
| Sensitivity — Stage I | 16.8% | CCGA3 (Stage I) |
| Sensitivity — Stage IV | 90.0% | CCGA3 (Stage IV) |
| CSO prediction accuracy | 93.4% | CCGA3 |
Evidence Programs (Cohorts)
- CCGA — 15,254 participants (case-control, three arms)
- PATHFINDER 1 — 6,662 participants (prospective, clinical practice)
- PATHFINDER 2 — 35,878 participants
- NHS-Galleri RCT — 142,826 participants (randomized controlled)
- Total > 385,000 participants
Regulatory Status
US: a laboratory-developed test (LDT) under CLIA; the FDA PMA application was filed on 29 January 2026; on 23 September 2026 the advisory panel delivered a mixed-favorable vote — safety 10-0, effectiveness 6-4, benefit/risk 7-2-1. Türkiye: applied under Ministry of Health-compliant biological material transfer, coordinated by the Özel Omega-Pro Genetic Disease Assessment Center. Samples are analyzed in GRAIL's CLIA/CAP-accredited US laboratory.
Interpretation Note
Sensitivity values vary strongly by stage (Stage I 16.8% vs Stage IV 90.0%). This shows that the test can produce a signal even at early stages but does not replace screening on its own, and cannot be used instead of diagnostic evaluation in symptomatic patients. All percentages were obtained under study conditions; individual patient interpretation must be done through physician evaluation.
References
- Klein EA et al. Ann Intern Med. 2021;174(7):883-890 (CCGA).
- Schrag D et al. Ann Oncol. 2021;32(9):1167-1177 (PATHFINDER).
- NHS-Galleri study protocol and interim reports (2023-2026).
Rx-only — prescription screening test. Galleri® is not a diagnostic test. A positive result does not mean a cancer diagnosis; a negative result does not rule out cancer. The test does not replace the routine cancer screenings recommended by your physician. Galleri® does not detect all cancers.