Find the Right Companion Diagnostic
Search by indication, biomarker, therapy, or test. Confirm which assay meets FDA requirements and see where it can be ordered, all in one place.
Featured Companion Diagnostics
Browse all →VENTANA HER2 Dual ISH DNA Probe Cocktail is an FDA-approved, dual-color chromogenic in situ hybridization assay that uses HER2 and chromosome 17 DNA probes to assess HER2 gene amplification in FFPE breast and gastric or gastroesophageal junction cancer tissue. Performed on VENTANA BenchMark instruments, it reports HER2/Chr17 ratios to classify tumors as HER2-negative or HER2-amplified for treatment planning.
PATHWAY anti-HER2/neu (4B5) Rabbit Monoclonal Primary Antibody is an FDA-approved, semi-quantitative immunohistochemistry reagent for detecting HER2 antigen in formalin-fixed, paraffin-embedded breast and gastric tissue on VENTANA BenchMark IHC/ISH instruments. Using standardized 0–3+ membrane staining criteria, it classifies tumors by HER2 protein expression to support HER2-directed treatment decisions.
Explore by workflow
Start with a cancer type or clinical scenario (e.g., metastatic NSCLC), then see which biomarkers, therapies, and tests apply.
You know the biomarker you care about (EGFR, NTRK, HER2-low). See where it matters and which tests qualify.
Start from a specific drug and confirm the required biomarker and eligible companion diagnostics.
Already have a test in mind? Jump straight to its profile to see how and where it can be used.
Know Your Companions™
An intuitive report that maps indications, biomarkers, biomarker details, therapies, and eligible tests. Built from FDA approvals and CDx labeling.
| Indication | Biomarker | Biomarker details | Drug / therapy |
|---|---|---|---|
| Breast Cancer | ERBB2 (HER2) | Gene amplification (ISH amplified) | ENHERTU + PERJETA |
| Non-Small Cell Lung Cancer (NSCLC) | ERBB2 (HER2) | Activating mutations in the tyrosine kinase domain (SNVs in exons 18-21 and exon 20 insertions) | HYRNUO |
| Endometrial Carcinoma (EC) | Microsatellite stable/MSS (Not MSI-High) | MSS (Not Microsatellite instability high/not MSI-H) | KEYTRUDA + LENVIMA |
View all 221 approvals and eligible tests.
Open Know Your Companions™ →For pharma teams
List your companion diagnostic on CDXtests.com to ensure it is discoverable, accurately represented, and easy for providers to find, understand, and order.
- • Single source of truth for your CDx
- • Clear therapy-to-test ordering pathways
- • Scalable infrastructure for launch and growth
For laboratories
If your lab performs an FDA-approved CDx or a validated LDT alternative, you can appear in provider workflows and support digital ordering through Casandra.
- • Be listed where providers search for companion diagnostics.
- • Connect to Casandra for streamlined ordering.
- • Align your offerings with Know Your Companions™ mapping.