# Shield

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

## TL;DR

The first FDA-approved blood test for colorectal cancer screening (2024), now optionally reporting other cancers too.

## Summary

Shield is Guardant Health's blood-based colorectal cancer screening test: it reads cell-free DNA for methylation patterns, fragmentation signatures and mutations that indicate a tumour. It was the first FDA-approved blood test for colorectal cancer screening (2024), for average-risk adults aged 45 and over with Medicare coverage. In the ECLIPSE study it detected 83% of colorectal cancers with 90% specificity, but only 13% of advanced adenomas, the precancerous lesions that colonoscopy removes to prevent cancer. Its value therefore lies in reaching people who decline colonoscopy or stool tests, and any positive result must be followed by colonoscopy. In 2025 a Shield MCD option added multi-cancer detection with Breakthrough designation. For a newcomer: a convenient blood test for bowel cancer that catches cancers well but polyps poorly.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-04
- Modality: Blood-based colorectal cancer screening test
- Mechanism: cfDNA methylation, fragmentomics, and mutations.
- Approvals: US 2024: Colorectal cancer screening, average-risk adults ≥45

## Sources

- FDA premarket approval P230009: Shield blood-based colorectal cancer screening test: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpma/pma.cfm?id=P230009

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Early-onset colorectal cancer (under 50)](https://onco.cc/cancers/early-onset-colorectal/)
- technologies: [Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood)](https://onco.cc/technologies/colorectal-screening/), [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [Multi-cancer early detection (MCED)](https://onco.cc/technologies/mced/), [Multitarget stool RNA test (ColoSense)](https://onco.cc/technologies/multitarget-stool-rna-test/)
- companies: [Freenome](https://onco.cc/companies/freenome/), [Guardant Health](https://onco.cc/companies/guardant-health/)
- roadmaps: [ctDNA tests roadmap: from a curiosity in plasma to blood tests that decide treatment](https://onco.cc/roadmaps/ctdna-tests/), [Early detection roadmap: organ screening → blood tests for many cancers](https://onco.cc/roadmaps/early-detection-roadmap/)
- bottlenecks: [The hardest cancers are found late](https://onco.cc/bottlenecks/b-early-detection/)
- ideas: [Mandatory interval-cancer audit for every blood-based screening test](https://onco.cc/ideas/idea-prev-interval-cancer-audit-blood-tests/), [Offer the blood test for bowel cancer only to people who refuse stool tests or colonoscopy](https://onco.cc/ideas/idea-prev-blood-crc-test-for-non-responders/)
- terms: [Screening](https://onco.cc/terms/screening/)
- pathways: [Intravasation & circulating tumour cells](https://onco.cc/pathways/intravasation-ctc-survival/)
- drugs: [Cancerguard](https://onco.cc/drugs/cancerguard/), [Cologuard](https://onco.cc/drugs/cologuard/), [Cologuard Plus](https://onco.cc/drugs/cologuard-plus/), [SimpleScreen CRC](https://onco.cc/drugs/simplescreen-crc/)
- trials: [ECLIPSE (Shield blood test)](https://onco.cc/trials/eclipse-shield/)

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