Breakthrough test performance

Galleri® is next-level cancer screening designed to detect the previously undetectable1

The Galleri test does not detect a signal for all cancers and not all cancers can be detected in the blood. False positive and false negative results do occur.

waist up studio portrait of a woman in blue t-shirt with gray hair wearing a stethoscope gazing off camera

The Galleri test does not detect a signal for all cancers and not all cancers can be detected in the blood. False positive and false negative results do occur.

Revolutionizing cancer screening with a clinically-validated blood test

Galleri is supported by clinical studies with over 20,000 individuals. Galleri’s test performance was validated in the PATHFINDER and CCGA3 studies.

A prospective study of a Multi-Cancer Early Detection Blood Test2

  • Cohort: >6,600 adults ages 50-79y without clinical suspicion of cancer, and with and without additional cancer risk factors from 7 U.S. sites - Intended use population

  • Study Design: Prospective, interventional, return-of-results study to evaluate the clinical implementation of an MCED test.

  • Study Objectives: Assess the extent of diagnostic testing required to achieve diagnostic resolution, evaluate test performance, and evaluate participant reported outcomes.

  • Key Outcomes: Adding MCED screening approximately doubled the number of cancers detected. Median time to diagnostic resolution was 79 days (shorter for true positive; longer for false positive). High accuracy of predicted cancer signal origin enabled targeted diagnostic evaluations. Most diagnostic evaluations involved imaging. Key performance metrics were validated and MCED screening was safely implemented. The results from PATHFINDER support feasibility of broad screening use of Galleri.

Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set1

  • Cohort: >4,000 participants without a prior history of cancer from 142 sites, 70% with newly diagnosed cancer, 30% cancer free at enrollment and at 1 year

  • Study Design: Case- controlled observational study to validate an MCED test regarding sensitivity, specificity and cancer signal origin prediction

  • Study Objectives: Validate a MCED test version further refined for use as a screening tool.

  • Key Outcomes: The Galleri test demonstrated high specificity with a low false-positive rate, sensitivity that varied by cancer class and increased with increasing cancer stage, high accuracy of CSO prediction and detected a cancer signal across a wide diversity of cancers and cancer stages. Results from CCGA3 support the feasibility of use as a complement to existing single-cancer screening tests.

Galleri sets the standard for multi-cancer early detection

To achieve the benefits of early detection while minimizing harms, multi-cancer early detection requires low false positive rates due to high specificity, accurate localization of organ/tissue origin, and higher sensitivity of the deadliest cancer types.3

close up image of the Galleri test box with a female physician out of focus in the background

Screening for many types of cancer

Galleri detects a signal shared by more than 50 cancer types1 with a single blood test, most of which lack routine screening tests. In a clinical study, Galleri approximately doubled the number of cancers detected with recommended screening.2 In the same study, 48% of confirmed cancers that were detected by Galleri were in stages I-II.2 Galleri goes beyond routine cancer screenings (breast, lung, colon, cervical, and prostate) to screen for many cancers.

blue bar graph illustrating multi cancer early detection testing nearly doubled the number of cancers detected with recommened screening

99.5% Specificity1,2

Galleri has a specificity of 99.5%, which means that it has a low false positive rate of 0.5%. A low false positive rate helps minimize unnecessary diagnostic procedures.

Specificity = The proportion of people without cancer who received "No Cancer Signal Detected" results.

43.1% Positive Predictive Value2

Galleri’s positive predictive value (PPV) is 43.1%, meaning that about 4 out of 10 individuals with a “Cancer Signal Detected” result are expected to have a confirmed cancer diagnosis following diagnostic work-up. Galleri’s PPV helps healthcare providers set expectations when discussing appropriate next steps for diagnostic work-up.

Learn more about Galleri's PPV

Positive Predictive Value = The proportion of people with "Cancer Signal Detected" results diagnosed with cancer

98.5% Negative Predictive Value2

The negative predictive value (NPV) for Galleri is 98.5%, which provides confidence that a "No Cancer Signal Detected" result is likely a true negative.

Negative Predictive Value = The proportion of people with "No Cancer Signal Detected" results without cancer.

88% Cancer Signal Origin Accuracy2

Galleri's highly accurate Cancer Signal Origin (CSO) prediction helps guide diagnostic evaluation. When a cancer signal is detected, Galleri predicts up to two Cancer Signal Origins by comparing the methylation pattern to the patterns of 21 possible CSO predictions. In study participants diagnosed with cancer (true positives), the first or second predicted CSO was accurate 88% of the time. In those study participants, the predicted CSO(s) was consistent with the type of cancer confirmed through diagnostic workup.2 Predicting the origin of the cancer signal helps healthcare providers select the appropriate follow-up diagnostic tests or procedures to confirm the diagnosis.1

Cancer Signal Origin Accuracy = The proportion of correctly predicted first (or second) CSO prediction(s) among study participants with cancer and "Cancer Signal Detected" results.

Galleri Test has 21 possible Cancer Signal Origin Predictions1
CSO Reported What Is Included
Anus Anus
Bladder, Urothelial Tract Bladder, Renal Pelvis, Urether, Urethra
Bone and Soft Tissue Skeletal muscle and other connective tissue, Vascular Tissue, Bone and cartilage
Breast Breast
Cervix Cervix
Colon/Rectum Colon, Rectum, Appendix
Head and Neck Oropharynx, Hypopharynx, Nasopharynx, Larynk, Lip and oral cavity (inluding oral tongue), Nasal cavity, Paranasal sinuses, Major salivary glands
Kidney Kidney
Liver, Bile Duct Liver, Intrahepatic bile duct
Lung Lung, Bronchus
Lymphoid Lineage Lymphoid Lineage
Melanocytic Lineage Melanocytic Lineage
Myeloid Lineage Myeloid Lineage
Neuroendocrine Cells of Lung or other Organs Neuroendocrine Cells of Lung or other Organs
Ovary Ovary, Fallopian tube, Primary peritoneum
Pancreas, Gallbladder Pancreas, Extrahepatic bile duct, Gallbladder
Plasma Cell Lineage Plasma Cell Lineage
Prostate Prostate
Stomach, Esophagus Stomach, Esophagus
Thyroid Gland Thyroid Gland
Uterus Uterus

76.3% sensitivity for 12 deadly cancers1

Galleri has high sensitivity (76.3%) for 12 deadly cancer classes* that comprise two-thirds of all cancer deaths.4 Higher sensitivity for the deadliest cancers helps minimize overdiagnosis and/or overtreatment of indolent cancers.3 More aggressive cancers, such as pancreatic cancer, tend to release more cell-free DNA into the bloodstream at early stages and are more likely to be detected by the Galleri test.1 The overall sensitivity for cancer detection is 51.5% for all cancers and across all stages. This provides the opportunity to detect many additional cancers when added to recommended single-cancer screening.

Sensitivity = The proportion of people with cancer who received "Cancer Signal Detected" results.

*Anus, bladder, colon/rectum, esophagus, head and neck, liver/ bile duct, lung, lymphoma, ovary, pancreas, plasma cell neoplasm, and stomach

Cancer Classes Sensitivity, proportion of true positives
Head and Neck
Urothelial Tract
Plasma Cell Neoplasm
Lymphoid Leukemia
Myeloid Neoplasm

See publications supporting Galleri test performance

Advancing cancer screening with ongoing clinical studies

GRAIL has and continues to conduct multiple studies with over 300,000 participants as part of its clinical development. To support and validate our technology, studies are being performed at leading health systems and community and academic medical centers in the U.S. and UK.

image depicting the logos of the network of insititutions who have participated or are participating in clinical studies of the Galleri test

Go further with Galleri in your clinical practice

Insights from the first 100,000 Galleri tests completed6


of test results were Cancer Signal Detected, consistent with clinical studies2


of Cancer Signal Detected results had predicted cancer signal origins representing cancers without guideline-recommended screening options

Hear from Galleri patients and providers

The Galleri test is recommended for use in adults with an elevated risk for cancer, such as those aged 50 or older. The Galleri test does not detect all cancers and should be used in addition to routine cancer screening tests recommended by a healthcare provider. Galleri is intended to detect cancer signals and predict where in the body the cancer signal is located. Use of Galleri is not recommended in individuals who are pregnant, 21 years old or younger, or undergoing active cancer treatment.

Results should be interpreted by a healthcare provider in the context of medical history, clinical signs and symptoms. A test result of No Cancer Signal Detected does not rule out cancer. A test result of Cancer Signal Detected requires confirmatory diagnostic evaluation by medically established procedures (e.g. imaging) to confirm cancer.

If cancer is not confirmed with further testing, it could mean that cancer is not present or testing was insufficient to detect cancer, including due to the cancer being located in a different part of the body. False-positive (a cancer signal detected when cancer is not present) and false-negative (a cancer signal not detected when cancer is present) test results do occur. Rx only.

The GRAIL clinical laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) and accredited by the College of American Pathologists. The Galleri test was developed and its performance characteristics were determined by GRAIL. The Galleri test has not been cleared or approved by the Food and Drug Administration. The GRAIL clinical laboratory is regulated under CLIA to perform high-complexity testing. The Galleri test is intended for clinical purposes.

  1. Klein EA, Richards D, Cohn A, et al. Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set. Ann Oncol. 2021;32(9):1167-77. DOI:

  2. Schrag D, McDonnall CH, Naduld L, et al. PATHFINDER: A Prospective Study of a Multi-Cancer Early Detection Blood Test. Presentation at European Society of Medical Oncology (ESMO) Congress September 9-13, 2022; Paris, France.

  3. Hackshaw A, Clarke CA, Hartman AR. New genomic technologies for multi-cancer early detection: Rethinking the scope of cancer screening. Cancer Cell. 2022;40(2):109-113. DOI:

  4. American Cancer Society. Cancer Facts & Figures 2022. Atlanta: American Cancer Society; 2022 GRAIL, LLC Data on file GA-2021-0065.

  5. Liu MC, Oxnard GR, Klein EA, et al. Sensitive and specific multi-cancer detection and localization using methylation signatures in cell-free DNA. Ann Oncol. 2020;31(6):745-759. DOI:

  6. 100,000 tests. GRAIL, LLC Data on File: GA-2022-0078.