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 →FDA-approved companion diagnostic for Muscle Invasive Bladder Cancer (MIBC)
PD-L1 IHC 28-8 pharmDx is an FDA-approved, qualitative immunohistochemical assay that uses monoclonal rabbit anti–PD-L1, clone 28-8, to detect PD-L1 protein in FFPE tumor tissue. Using the EnVision FLEX system on the Autostainer Link 48, it reports the percentage of tumor cells with membrane staining to classify PD-L1 expression and support PD-1/PD-L1–directed treatment decisions.
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.
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 |
|---|---|---|---|
| Muscle Invasive Bladder Cancer (MIBC) | Circulating tumor DNA (ctDNA) molecular residual disease (MRD) | ctDNA MRD | TECENTRIQ |
| Esophageal squamous cell carcinoma (ESCC), and gastric, gastroesophageal junction (GEJ) and esophageal adenocarcinoma | PD-L1 | PD-L1 protein expression [Combined Positive Score (CPS) ≥ 1] | OPDIVO |
| Breast Cancer | ERBB2 (HER2) | gene amplification | ENHERTU |
View all 243 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.