FAQs

for Providers about the Galleri® test


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Galleri is a cancer screening test that leverages DNA sequencing and pattern-recognition technology to screen for the presence of a cancer signal and predict its most likely origin. Galleri uses DNA sequencing technology to analyze DNA fragments circulating in the blood, also known as cell-free DNA (cfDNA). Both non-cancer and cancer cells release cfDNA into the blood, but cfDNA from cancer cells has methylation patterns that are specific to cancer. Galleri checks over 1 million methylation sites covering >100,000 genomic regions in cfDNA and applies machine learning and pattern-recognition to identify abnormal methylation patterns that could signal the presence of cancer.1,2

DNA methylation patterns are also organ and tissue specific. When a cancer signal is detected, Galleri analyzes DNA methylation patterns to predict the tissue or organ associated with the cancer signal (known as Cancer Signal Origin). The Cancer Signal Origin information can help guide the diagnostic workup to confirm the presence of cancer by standard medical practice.2,3

Learn more about How Galleri Works.

In a clinical study which included 2,823 cancer participants and 1,254 non cancer participant controls, the Galleri test detected a cancer signal shared by more than 50 cancer types as defined by AJCC.2,4

The Galleri test comprises a two-step process. 

First, Galleri detects a cancer signal by analyzing methylation patterns in cell-free DNA (DNA fragments circulating in the blood). Second, Galleri predicts the tissue or organ associated with the cancer signal, also known as the Cancer Signal Origin (CSO). Cell-free DNA (cfDNA) methylation patterns are both cancer and organ/tissue-specific. When a cancer signal is detected, Galleri applies pattern-recognition to compare the DNA methylation pattern in the patients’ cfDNA to the patterns of 21 possible CSO predictions. If the CSO prediction has a very strong match to the patient’s methylation pattern, then only one CSO prediction is reported. Otherwise, the two best CSO predictions are reported.2,3


Cancer signal origin information helps healthcare providers select appropriate diagnostic tests and procedures when a cancer signal is detected with Galleri.3 In the PATHFINDER study, Galleri demonstrated 88% accuracy in predicting the top two Cancer Signal Origins among true positive study participants. In those study participants, the predicted CSO(s) was consistent with the type of cancer confirmed through diagnostic workup. Galleri's ability to predict the Cancer Signal Origin can help streamline diagnostic evaluation by helping guide providers to appropriate diagnostic tests for an anatomical site.3,5

Galleri analyzes cell-free DNA (DNA fragments circulating in the blood) to detect abnormalities in methylation patterns that could signal the presence of cancer.2 Methylation is a process used by cells to regulate gene expression.6 Both cancer and non-cancer cells shed DNA into the bloodstream. Sensitivity is related to the availability of cancer-specific cfDNA in the blood. Apart from differences in tumor burden (e.g., stage), cfDNA availability is impacted by a variety of biologic and physiologic factors that modulate the rate of cfDNA release and clearance such as tissue perfusion, cell turnover activity, and cell proliferation rate. Movement of cfDNA from a tumor into circulation can be limited by anatomic location.7 Less aggressive cancers, such as many thyroid cancers, release less cell-free DNA into the bloodstream and are less likely to be detected. 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.2 Higher Galleri sensitivity for the deadliest cancers helps minimize overdiagnosis and/or overtreatment of indolent cancers. Galleri has high sensitivity (76.3%) for 12 deadly cancers that comprise two-thirds of all cancer deaths,8 and an overall sensitivity of 51.5% for all cancers and across all stages.2 In the PATHFINDER study, Galleri approximately doubled the number of cancers detected with recommended screening. Nearly half of the cancers detected by Galleri were in stages I-II.3 These detection rates suggest that adding Galleri to guideline-recommended cancer screening has the potential to increase detection of early-stage cancers and of cancers that lack screening options today.

Learn more about Galleri Test Performance.

False positives occur with any type of cancer screening (such as mammography or stool-based colon screening). The Galleri test has a low false-positive rate of 0.5%.2,3 This means that in approximately 200 people without cancer, 1 person would be expected to receive a false positive result from Galleri. A low false positive rate – which can minimize the possibility of false alarms, reducing unnecessary anxiety, costs, and medical risks of unneeded follow-up procedures – is a key component to a successful broad-based, population cancer screening test.5

Learn more about Galleri Test Performance.

Galleri is recommended for use in adults with an elevated risk for cancer, such as those aged 50 or older. Galleri should be used in addition to guideline-recommended single-cancer screenings, such as mammography, colonoscopy, low-dose computed tomography, PSA, or cervical cancer screenings. Use of Galleri is not recommended in individuals who are pregnant, 21 years old or younger, or undergoing active cancer treatment.

Guideline-recommended screening tests have been proven to reduce deaths due to cancer.9 The Galleri test does not detect a signal for all cancers and not all cancers can be detected in the blood. Galleri should be used in addition to guideline-recommended cancer screenings, such as mammography, in order to maximize the chances of detecting cancer early. Galleri detects a cancer signal shared by more than 50 types of cancer, most of which lack recommended screening tests.2 In the PATHFINDER study, Galleri approximately doubled the number of screen detected cancers.3

Galleri screens for the presence of a signal common to many cancers, whereas genetic tests predict the risk of developing cancer in the future. Galleri analyzes methylation patterns on cell-free DNA to screen for the current presence of cancer whereas genetic risk assessments look for DNA mutations that indicate an increased risk for developing cancer in the future. Galleri can be added to routine cancer screenings to maximize the chances of detecting cancer early whereas genetic tests are typically performed only once.2,3,10

The Galleri test must be ordered by a licensed healthcare provider with prescriptive authority in the state in which they will be prescribing Galleri. This may include physicians, nurse practitioners, or physician assistants.

The Galleri test is currently not included in cancer screening guidelines.

Modeled data suggests that adding Galleri to annual wellness visits can improve the chances of finding cancer early.11,12 It is up to the patient’s healthcare provider to determine the appropriate screening interval based on the individual’s underlying risk factors.

The Galleri test is only commercially available in the US at this time.

The list price for the Galleri test is $949. Contact GRAIL Customer Service at 833−694−2553 or fill out a support request if you have questions about pricing.

The Galleri test is gaining coverage with payers, but as the test is new to the market and represents significant innovation in cancer screening, not all insurers are covering the Galleri test. Patients may elect to pay for the test themselves and/​or check with their insurer for coverage before requesting the test.

GRAIL offers patients convenient options to pay for the Galleri test. Patients may contact GRAIL customer service at 833−694−2553 to learn more about enrolling in a flexible payment plan.

For a patient paying directly for the test in full (patient self-pay), credit card information can be added to the paper Test Requisition Form at the time of order.

Patients can also pay for the test online with all major credit cards (American Express, Visa, Mastercard, and Discover) once their test has been processed by the GRAIL lab. Additionally, payment can be made over the phone by calling GRAIL Billing Support at 858-333-5986 or by mailing a physical check, GRAIL ID and bottom portion of invoice to GRAIL, Inc. at the address provided below:

GRAIL, LLC
Dept LA 25195
Pasadena, CA 91185 – 5195

Patients may be able to use pre-tax dollars in a flexible spending account (FSA) or health savings account (HSA) to pay for the Galleri test and should check with their FSA/HSA account administrator or insurance company to determine eligibility.

All or a portion of the Galleri test may be covered by some individual employers as an employer-sponsored benefit. Patients should contact their employer to learn whether they cover the Galleri test and to check their availability.

For electronic orders via the Provider Portal, patients will be invoiced via email and/or mail at the address(es) provided on the Test Requisition Form once the sample is received in the laboratory.

Patients should check with their FSA/HSA account administrator or insurance company to determine eligibility.

If you are a returning provider, sign in to the Provider Portal to order the Galleri test.
If you are a new provider, please visit the Order Test page to start ordering the Galleri test.

Specimen requirements include:

  1. Specimen Type: Human Whole Blood
  2. Container: Streck Cell-Free DNA® Blood Collection Tubes (included as part of the specimen collection kit)
  3. Volume: 10mL x 2 tubes
  4. Sample Storage: Ambient temperature (not to extend outside the 1-40℃ (33.8-104℉) range)
  5. Stability: Up to 7 calendar days

Specimen rejection criteria include:

  1. Tubes other than the Streck Cell-Free DNA Blood Collection Tubes
  2. Less than 3mL of whole blood per collection tube
  3. Unlabeled specimens
  4. Severely damaged or dangerously packaged specimens
  5. Specimens with grossly hemolyzed plasma
  6. Specimens submitted or stored at temperature outside of 1-40℃ (33.8-104℉)
  7. Collection date more than 7 days prior to the start of processing


Collection kits should be stored at room temperature. Avoid storing the collection kits in places that experience high or low temperatures like window sills or near central heating vents.

No, the Galleri test blood draw requires no preparation or fasting by the patient. Fasting for other blood draws will not affect the Galleri test results if blood is drawn at the same time.

Test results should be available to the ordering provider about 2 weeks from the date the sample arrives at GRAIL’s laboratory. Typically, a sample will arrive at the laboratory in 1 to 2 business days after the blood sample is shipped. 

In the rare scenarios where a sample fails, you will be notified about your patient’s sample status.

The Galleri test results are shared with the ordering healthcare provider via the online Provider Portal and/or via automatic fax notifications. An email notification will be sent to the ordering provider when new test result reports are ready in the Provider Portal.

If you or a patient would like to cancel a test order, please contact GRAIL Customer Service at 833−694−2553 or fill out a support request.

The Galleri test did not detect DNA methylation patterns that are associated with cancer in the patient’s blood sample. The Galleri test does not detect a signal for all cancers, and not all cancers can be detected in the blood. A "No Cancer Signal Detected" result does not completely rule out the possibility of cancer and does not predict risk of developing cancer in the future. In the PATHFINDER clinical study, on average, fewer than 2 out of 100 people with a "No Cancer Signal Detected" result received a cancer diagnosis (Negative Predictive Value or NPV was 98.5%).3 Individuals who receive a "No Cancer Signal Detected" result should continue with all recommended cancer screening options at intervals appropriate for the individual. The use of the Galleri test should not replace, supersede, or otherwise alter the use or frequency of standard of care cancer screening or detection modalities.

A "Cancer Signal Detected" result means that the Galleri test detected DNA methylation patterns that are often associated with cancer in the patient’s blood sample. In the PATHFINDER study, on average, 4 out of 10 people with a "Cancer Signal Detected" result received a cancer diagnosis (Positive Predictive Value or PPV was 43%).3

The Galleri test is a screening test, not a diagnostic test. A "Cancer Signal Detected" result is not a diagnosis of cancer. It is important to follow up with diagnostic testing to confirm the presence of cancer. 

When the Galleri test detects a cancer signal, it assigns the signal to one or two of 21 cancer signal origins (CSO) based on distinct DNA methylation data that reflect the biology and tissue or organ associated with the cancer signal.2 The "CSO information" is provided to help guide the diagnostic evaluation needed to confirm the presence of cancer and the cancer type.

When the Galleri test detects a cancer signal, results must be confirmed by diagnostic evaluation recommended by qualified health care professionals in accordance with standard medical practice.2 These results should be interpreted in the context of the individual's clinical risk factors. Diagnostic decisions are the responsibility of the treating physician. 

GRAIL offers clinical support and resources to help ensure providers and patients are well supported after a "Cancer Signal Detected" result. For more information about our clinical support resources, please contact GRAIL Customer Service at 833−694−2553 or fill out a support request.

GRAIL offers clinical support and resources to ensure you and your patients are well supported after a "Cancer Signal Detected" result. In the event that a diagnostic evaluation after a "Cancer Signal Detected" result does not confirm cancer, patients may be eligible for a complimentary Galleri retest within 3 – 6 months after the original test result. To initiate a no-charge retest or obtain more information on our clinical support resources, please contact GRAIL Customer Service at 833−694−2553 or fill out a support request.

A test may be canceled for a variety of reasons, which include healthcare provider or patient requests, exceeding the specimen stability window, and failure to meet sample quality requirements, among others. For more information on your specific cancellation, please contact GRAIL Customer Service at 833−694−2553 or fill out a support request.

Galleri test results can be accessed via the Provider Portal.

For more information about a specific patient’s test result, please contact GRAIL Customer Service at 833−694−2553 or fill out a support request.

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. 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: https://doi.org/10.1016/j.annonc.2020.02.011.

  2. 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: https://doi.org/10.1016/j.annonc.2021.05.806.

  3. 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.

  4. Amin MB, et al. (Eds.). AJCC Cancer Staging Manual (8th edition). Springer International Publishing: American Joint Commission on Cancer; 2017.

  5. Hackshaw A, Clarke C, Hartman, AR. New genomic technologies for multi-cancer early detection: Rethinking the scope of cancer screening. Cancer Cell. 2022;40(2):109-113. DOI: https://doi.org/10.1016/j.ccell.2022.01.012.

  6. Wajed S, Laird P, DeMeester T. DNA Methylation: An alternative Pathway to Cancer. Ann Surgery. 2001;234(1):10-20. DOI: https://doi.org/10.1097/00000658-200107000-00003.

  7. Bronkhorst AJ, Ungerer V, Holdenrieder S. The emerging role of cell-free DNA as a molecular marker for cancer management. Biomol Detect Quantif. 2019 Mar 18;17:100087. DOI: https://doi.org/10.1016/j.bdq.2019.100087.

  8. American Cancer Society. Cancer Facts & Figures 2022. Atlanta: American Cancer Society; 2022 https://www.cancer.org/research/cancer-facts-statistics/all-cancer-facts-figures/cancer-facts-figures-2022.html. Data on file GA-2021-0065.

  9. NIH/National Cancer Institute. Cancer Screening/Research. Accessed 3May2023. https://www.cancer.gov/about-cancer/screening/research/what-screening-statistics-mean.

  10. NIH/National Cancer Institute. The genetics of cancer. Accessed 3Mar2023. https://www.cancer.gov/about-cancer/causes-prevention/genetics#:~:text=Cancer%2Drelated%20genetic%20changes%20can,from%20one%20of%20our%20parent.

  11. Hackshaw, A., Cohen, S.S., Reichert, H. et al. Estimating the population health impact of a multi-cancer early detection genomic blood test to complement existing screening in the US and UK. Br J Cancer. 2021 125, 1432–1442. DOI: https://doi.org/10.1038/s41416-021-01498-4.

  12. Sasieni P, Clarke CA, Hubbell E. Impact of MCED screening interval on reduction in late-stage cancer diagnosis and mortality. Presentation at European Society for Medical Oncology (ESMO) Virtual Congress; September 16-21, 2021.