# Guardant Reveal

Source: https://onco.cc/drugs/guardant-reveal/  
OnCo record `guardant-reveal` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A blood test for leftover cancer after surgery that needs no tumour sample, so results come faster than tumour-informed tests.

## Summary

Guardant Reveal launched in 2021 as the first tissue-free MRD test, initially for stage II-III colorectal cancer, with Medicare coverage for colorectal cancer surveillance and later breast and lung indications. Tumour-naive design gives a result within about a week of surgery and suits patients whose tissue is unavailable, at the cost of somewhat lower sensitivity than bespoke tumour-informed panels such as Signatera. Published colorectal data show ctDNA positivity after surgery carries a high risk of recurrence, and serial negative results are strongly reassuring. It is a laboratory-developed test under CLIA.

## Fields

- Kind: Treatment
- Status: established
- Last checked: 2026-09-10
- Tags: test
- Brand: Guardant Reveal
- Modality: Tumour-naive ctDNA minimal residual disease test (methylation and genomic)
- Mechanism: Blood-only assay combining somatic variant detection with cancer-specific methylation signals, so no tumour tissue is needed to design the test.

## Notes

- What a result means: ctDNA detected after surgery means a high chance of recurrence and a case for closer follow-up or adjuvant therapy; not detected is reassuring but not a guarantee.
- Colorectal cancer: a tumour-naive residual disease assay combining methylation and mutation signal, used in the same postoperative setting as the tumour-informed tests but without needing tumour tissue; the randomised evidence in colorectal cancer is for tumour-informed assays (Tie 2022), so the equivalence is inferred rather than shown.

## Sources

- Guardant Reveal (page moved; nearest live section): https://guardanthealth.com/

## Connected records

- drugs: [RaDaR](https://onco.cc/drugs/radar-mrd/), [Signatera](https://onco.cc/drugs/signatera/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- technologies: [CEA surveillance after colorectal cancer surgery](https://onco.cc/technologies/cea-surveillance-colorectal/), [DNA methylation profiling](https://onco.cc/technologies/methylation-profiling/), [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/)
- companies: [Guardant Health](https://onco.cc/companies/guardant-health/)
- terms: [Circulating tumour DNA (ctDNA)](https://onco.cc/terms/ctdna/), [Minimal / molecular residual disease (MRD)](https://onco.cc/terms/mrd/), [Tumour-informed versus tumour-naive ctDNA assays](https://onco.cc/terms/tumour-informed-assay/)
- trials: [Adding Capivasertib to Standard Treatment in HR Positive, HER2 Negative Metastatic Breast Cancer Based on ctDNA Testing](https://onco.cc/trials/nct07802626/)
- roadmaps: [ctDNA tests roadmap: from a curiosity in plasma to blood tests that decide treatment](https://onco.cc/roadmaps/ctdna-tests/), [Diagnostics roadmap: stains → gene panels → blood tests that decide treatment](https://onco.cc/roadmaps/diagnostics-roadmap/)
- biomarkers: [ctDNA MRD positivity (molecular residual disease after curative treatment)](https://onco.cc/biomarkers/ctdna-mrd-positive/)

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