Galleri® Multi-Cancer Early Detection Test
A GRAIL laboratory-developed blood test that screens for a shared cancer signal across many cancer types.
- Screening for a signal shared across many cancer types, including some with no routine screening test
- Predicting the likely tissue of origin when a signal is found, which is what makes a positive actionable
- Added on top of guideline-recommended screening — never in place of it
A result of “no cancer signal detected” is not an all-clear. Overall sensitivity is about 51.5%, so roughly half of cancers present would still return a negative result. Continue all recommended screening regardless.
Indicative price · confirmed after eligibility · prescription treatment
How Galleri works
Standard cancer screening covers a handful of cancers — breast, colon, cervical, lung and prostate, depending on your risk. Those programs save lives, and they should be your foundation.
But most cancer deaths in the US come from cancers with no routine screening test at all. That's the gap Galleri® is built for: a single blood draw looking for a signal shared across many cancer types, added on top of the screening you should already be doing.
It is a genuinely promising technology. It also has real limits that are easy to misunderstand, and misunderstanding them is the main way this test could cause harm rather than prevent it. This page covers both.
Cancers shed fragments of DNA into the bloodstream. Those fragments carry chemical marks — methylation patterns — that differ from healthy cells and, importantly, differ in ways that vary by tissue of origin. Galleri® analyzes those patterns from a standard blood draw. If a cancer signal is detected, the test also predicts where in the body it most likely originated, which is what makes a positive result actionable rather than merely alarming. In PATHFINDER 2, that origin prediction was correct in 91.3% of confirmed cases.
How it works here
Every plan follows one path. Each step feeds the next. See the All Treatments approach.
- 01
Measure
We baseline your labs, history, and goals.
- 02
Plan
A clinician decides whether this fits — and what else might serve you.
- 03
Act
If appropriate, you start with clear guidance and high-touch support.
- 04
Track
We monitor how you respond on a defined cadence.
- 05
Adjust
Protocols are refined over time. Guided care, not a kit in the mail.
What the numbers actually say
Most pages selling this test quote the impressive figures and skip the sobering one. Both belong here.
| Measure | Figure | What it means for you |
|---|---|---|
| Specificity | 99.6% | False alarms are rare — about 4 in 1,000 people without cancer get a positive result |
| Positive predictive value | ~60% | If you test positive, roughly 6 in 10 turn out to have cancer. A positive is serious but not a diagnosis |
| Cancer signal origin accuracy | 91.3% | When cancer is confirmed, the predicted location was right nine times out of ten |
| Sensitivity — 12 deadliest cancers | 76.3% | Strong performance against the cancers responsible for around two-thirds of US cancer deaths |
| Sensitivity — all cancers, all stages | 51.5% | The number that matters most. Galleri misses roughly half of all cancers present |
| Added detection vs standard screening alone | 6.5× | In PATHFINDER 2 (35,878 participants), adding Galleri detected 6.5 times more cancers than screening alone |
| Invasive follow-up procedures | 0.6% | Of all participants, fewer than 1 in 100 underwent an invasive procedure after a positive |
Scroll the table sideways to compare →
The honest summary: Galleri is very good at not crying wolf, and moderately good at finding cancer. Those are different things, and the second one is where people get misled.
Why “no cancer signal detected” is not an all-clear
This deserves its own section because it is the single most important thing on this page.
With overall sensitivity around 51%, a negative Galleri result means the test did not find a signal — not that cancer is absent. Roughly half of cancers present would still return “no cancer signal detected.”
The danger isn't the test. It's what someone might do with a reassuring result: delay a mammogram, put off a colonoscopy, or dismiss a symptom that warranted attention. A negative Galleri result should change none of those decisions.
If you have a symptom, it needs investigating regardless of what this test said. If you're due for guideline-recommended screening, go. Galleri adds to that foundation. It cannot substitute for any part of it, and a clinic that lets you believe otherwise has done you real harm.
What a positive result actually involves
Worth understanding before you test, because roughly 4 in 10 positives are not cancer.
A cancer signal detected result triggers a diagnostic workup — typically imaging and often a biopsy, directed by the predicted tissue of origin. In PATHFINDER 2 the median time to diagnostic resolution was 48 days, so there's a period of genuine uncertainty to sit with.
The trial also measured what that does to people. Anxiety rose after a positive result and returned to baseline within twelve months. That's reassuring at a population level and still means some weeks of worry, including for the 40% who turn out not to have cancer.
None of this is an argument against the test. It's an argument for going in with your eyes open, and for only testing if you'd actually be willing to follow through on a positive.
Delivery
A standard lab blood draw; results are reviewed with your clinician.
Who it's appropriate for
Galleri® is generally considered for adults 50 and over, or younger adults with elevated risk — a significant family history, a known genetic predisposition, or another clinical reason. It's most likely to make sense if you're already up to date on your guideline-recommended screening, you understand that a negative result changes nothing about that, and you would genuinely pursue a diagnostic workup if a signal were found. It's less likely to make sense if you're using it as a substitute for screening you've been avoiding, if a period of diagnostic uncertainty would be unmanageable for you right now, or if you have a current cancer diagnosis or are under active investigation — in which case it isn't the right tool. If you're building a baseline more broadly, start with a comprehensive blood panel and lab testing.
Often considered alongside
Comprehensive Lab Panel
A comprehensive blood panel establishing your baseline across key health markers.
View treatmentMethylation Health Panel
A panel assessing the methylation pathway and its B-vitamin cofactors.
View treatmentProducts marked Compounded are prepared by a licensed compounding pharmacy under a prescription written for you. Compounded medications are not FDA-approved and are not equivalent to or interchangeable with any branded product.
An honest word on the evidence
Galleri® is a laboratory-developed test. It has not been cleared or approved by the FDA, and it is not currently part of any guideline-recommended screening program. It is performed by a single CLIA-certified, CAP-accredited laboratory. The evidence base is substantial and growing — PATHFINDER 2 enrolled more than 35,000 participants and was presented at the 2026 ASCO Annual Meeting. What that evidence shows clearly is that Galleri detects cancers that standard screening misses, and that most of those are caught at earlier stages. What it has not yet shown is the outcome that ultimately matters: whether people screened with Galleri live longer than people who aren't. Detecting more cancer earlier is a strong proxy for that, and it isn't the same thing. Larger trials designed to answer the mortality question are ongoing, and until they report, the honest framing is promising and not yet proven at the level of guideline screening.
References
Government and professional-society sources consulted for this page.
- Cancer Screening Overview — National Cancer Institute
- Recommendation Topics — U.S. Preventive Services Task Force
Frequently asked questions
No. It's an addition to guideline-recommended screening, not a replacement for any of it. This is the most important thing to understand about the test.
It points toward the likely tissue of origin and your clinician arranges diagnostic follow-up — typically imaging, often a biopsy. A signal is not itself a diagnosis: around 6 in 10 positive results are confirmed as cancer. Median time to resolution in the PATHFINDER 2 trial was 48 days.
Specificity is 99.6%, so false positives are uncommon. Overall sensitivity across all cancers and stages is 51.5%, rising to 76.3% for the twelve cancers responsible for around two-thirds of US cancer deaths. In plain terms: a positive result is meaningful, and a negative result misses roughly half of cancers present.
No, and this matters. “No cancer signal detected” means no signal was found, not that cancer is absent. With overall sensitivity around 51%, about half of cancers would still return a negative result. Continue all recommended screening and investigate any symptom regardless.
It screens for a signal shared across many cancer types, including a number with no routine screening test at all. It does not detect all cancers, and performance varies considerably by cancer type — more aggressive cancers tend to shed more DNA and are detected more readily.
No. It's a laboratory-developed test performed by a single CLIA-certified, CAP-accredited laboratory, and it has not been cleared or approved by the FDA.
Generally not, because multi-cancer early detection isn't yet part of guideline-recommended screening. Diagnostic follow-up after a positive result is usually handled differently from the screening test itself.
Elevated risk is one of the reasons it's considered in adults under 50. It's worth discussing alongside whether genetic counseling or risk-specific screening would serve you better — for some family histories, a targeted approach is more informative than a broad one.
That depends on how you weigh a real chance of catching an otherwise-undetected cancer early against the cost, the possibility of a false positive and its workup, and the fact that mortality benefit hasn't yet been demonstrated. It's a reasonable choice for someone already screening properly who wants an additional layer. It's the wrong choice for someone hoping to replace screening with a blood test.
See if Galleri® Multi-Cancer Early Detection Test fits your plan
The right plan begins with knowing where you are. Start with a short eligibility check and a baseline — and we'll tell you, honestly, what fits.
We measure first. Then we act.
ACT 2 Health provides clinician-led care. Treatments described are available only to eligible patients following clinical evaluation and within applicable regulations. This page is educational and is not medical advice. Individual results vary. Performance figures are those published by GRAIL and reported from the PATHFINDER 2 study.