Guardant360 CDx
Companion Diagnostic
Guardant360 CDx is an FDA-approved companion diagnostic used to help identify patients who may be eligible for targeted therapies.
Use
Guardant360 CDx is an FDA‐approved liquid biopsy test that performs comprehensive genomic profiling using circulating tumor cell‐free DNA (cfDNA) from a blood sample. It identifies somatic mutations across a broad panel of cancer‐related genes to guide selection of targeted therapies, including companion diagnostic indications: KRAS G12C for LUMAKRAS (sotorasib), ERBB2 activating mutations for ENHERTU (fam‑trastuzumab deruxtecan‑nxki), ESR1 missense mutations for ORSERDU (elacestrant), and EGFR alterations for TAGRISSO (osimertinib), RYBREVANT (amivantamab), as well as MSI‐High status for immunotherapy eligibility. The test delivers results within approximately 7 calendar days, offering a less invasive and faster alternative to tissue biopsy for oncologic decision‑making.
Special Instructions
Specimens must be collected in Streck Cell‑Free DNA Blood Collection Tubes (BCTs) provided in the kit. The test is supported by mobile phlebotomy and Guardant Access programs to assist ordering, billing, insurance verification, and financial assistance. Negative results for companion diagnostic biomarkers should reflex to tissue biopsy if feasible.
Limitations
The test analyzes ctDNA in plasma and might not detect alterations if circulating tumor DNA is insufficient. A negative result for companion diagnostic biomarkers should be reflexed to tissue-based testing using an FDA‑approved tumor tissue test when feasible.
FDA ApprovedCompanion Diagnostic
Methodology
NGS (CGP)
Biomarkers
Result Turnaround Time
7 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
20 mL whole blood
Minimum Volume
4 mL whole blood (in each of two tubes)
Container
Streck Cell‑Free DNA BCT
Collection Instructions
Use only Streck Cell‑Free DNA BCTs provided in kit; avoid freezing or refrigeration, ship ambient.
Storage Instructions
Ship with room‑temperature gel pack; avoid temperature extremes.
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