The VENTANA Claudin 18 (43-14A) RxDx Assay is an FDA-approved qualitative immunohistochemical assay using a mouse monoclonal anti-Claudin 18 antibody intended for use in the assessment of Claudin 18 protein in formalin-fixed, paraffin-embedded (FFPE) gastric cancer tissue on a VENTANA BenchMark ULTRA instrument. Claudin 18 is indicated as an aid in identifying patients with Gastric Adenocarinoma including Gastroesophageal Junction (GEJ). Tumors that have Claudin 18 expression in ≥75% of tumor cells staining at 2+ and/or 3+ intensity may be eligible for treatment with VYLOY® (zolbetuximab).
Claudin 18 FDA (VYLOY®) for Gastric/GEJ Adenocarcinoma
- Immunohistochemistry (IHC)
- Epic Aura Integration
Specimen Requirements
Paraffin Block: 1 Block sent with a cold pack. No zinc or mercury fixatives. H&E: 1 unstained slide cut at 4-5 microns required. Cut Slides: 2 to 3 unstained slides cut at 4-5 microns. 1 slide per antibody/probe ordered. >100 viable tumor cells per probe set. Positively charged slides in 10% NBF. No zinc or mercury fixatives.
Storage and Transportation
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. NYS clients please provide date and time of Collection.
CPT Code(s)*
88360x1
Turnaround time
1-2 Days
Global: 2 Days
Tech-Only (stain only): 24 Hours
Level of Service
- Global
- Tech Only
Integrations
- Epic Aura
New York Approved: Yes
*The CPT codes provided with our test descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.
Biomarkers
Immunohistochemistry (IHC)
| Expression | |||||
|---|---|---|---|---|---|
| Claudin-18 | CLDN18 | ||||
Last Updated: March 10, 2026