Liquid biopsy (ctDNA)
A blood test that looks for tumour genetic material to supplement or partly replace tissue testing.
Not a diagnosis and not final medical advice. Must be reviewed by a doctor.
Purpose of the test
- Assessing molecular markers when tissue harvesting is difficult.
- Monitor marker changes throughout treatment in specific contexts.
Informs decisions
- Suitability of targeted therapy when tissue is not available.
- Marker changes after progression.
How the test is done
Blood is drawn, plasma is separated, and tumor genetic material is analyzed with a sensitive sequencing platform.
- Sample type
- Blood
- Estimated result time
- Generally one to two weeks.
Limitations
- A negative result does not always mean the marker is absent (the number of tumors detected may be low).
- Sensitivity varies between platforms and between patient conditions.
- Positive results often require confirmation by tissue examination.
Related
Cancer types
Not displayed
TanyaKanker does not display test-cost estimates. Ask the laboratory or facility providing the test for cost details directly.
Sources
- NCI Dictionary of Cancer Terms(lembaga)
Next steps
These suggestions come from links between entries in TanyaKanker's database, not from a medical judgement. Each suggestion includes why it appears.
To check
- Lung Cancer
Cancer type
Reason: Memerlukan pemeriksaan
- Targeted therapy
Treatment category
Reason: Memerlukan pemeriksaan
- ALK
Biomarker
Reason: Diperiksa melalui
- BRAF
Biomarker
Reason: Diperiksa melalui
- EGFR
Biomarker
Reason: Diperiksa melalui
- KRAS
Biomarker
Reason: Diperiksa melalui
What you can do
- Upload medical reports
Build a case summary in twelve steps
Reason: Often the most useful next step after reading this page
- Request a second opinion
Review of the treatment plan
Reason: Relevant when a treatment plan is being considered
- Consult a navigator
A request is recorded with this page context
Reason: For asking the next step directly
Recently updated
- Leukemia
Cancer page
Date: Data revision 2026-09-10
- Brain Cancer
Cancer page
Date: Data revision 2026-09-10
- Pancreatic Cancer
Cancer page
Date: Data revision 2026-09-10
- Testing Osimertinib as a Treatment for Lung Cancers With an EGFR Exon 20 Change
NCT03191149 - Phase 2
Date: Registry update in the last 30 days (2026-10-15)
Want to follow changes on this topic? Save the page or follow the topic so it is easy to find again. View saved items.
Prepare for your next consultation
Use the free six-question tool to prepare questions for your doctor.