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HelpTest Code CLD18 Claudin 18 (CLDN18) (43-14A), Semi-Quantitative Immunohistochemistry, Manual
Shipping Instructions
Attach the green "Attention Pathology" address label (T498) to the outside of the transport container before putting into the courier mailer.
Necessary Information
A pathology/diagnostic report and a brief history are required.
Specimen Required
Specimen Type: Tissue
Supplies: Pathology Packaging Kit (T554)
Collection Instructions: Formalin-fixed, paraffin-embedded tissue block; or 3 unstained glass, "positively charged" slides with 4-microns formalin-fixed, paraffin-embedded tissue
Additional Information: One slide will be stained with hematoxylin and eosin and returned.
Useful For
Identification of tumor cells expressing claudin 18
As an aid in screening patients who may be eligible for VYLOY (zolbetuximab) treatment
Method Name
Immunohistochemistry (IHC)
Reporting Name
CLDN18, SemiQuant IHC, ManualSpecimen Type
SpecialSpecimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Special | Ambient (preferred) | ||
| Refrigerated | |||
Reject Due To
| Decalcified paraffin embedded tissue Wet/frozen tissue Cytology smears Nonformalin fixed tissue including alcohol-formalin-acetic acid (AFA), 95% ethanol, PREFER fixatives or Zinc formalin Nonparaffin embedded tissue Noncharged slides ProbeOn slides |
Reject |
Clinical Information
Claudin 18 (CLDN18) is a member of the claudin protein family that regulates cell adhesion. A qualitative immunohistochemistry assessment using mouse monoclonal anti-claudin 18, clone 43-14A, serves as a biomarker in gastric and gastroesophageal junction cancer and may aid in identifying patients eligible for VYLOY (zolbetuximab) treatment.
Reference Values
An interpretive report will be provided.
Interpretation
Claudin 18.2 is a biomarker for gastric and gastroesophageal junction cancer. When positive (defined as at least moderate membranous staining in greater than or equal to 75% of viable tumor cells), it predicts response to zolbetuximab which has been approved for the treatment of gastric and gastroesophageal adenocarcinoma.
Cautions
This test has been validated for nondecalcified paraffin-embedded tissue specimens fixed in 10% neutral-buffered formalin. Recommended fixation time is between 6 and 48 hours. This assay has not been validated on tissues subjected to the decalcification process or use of alternative fixatives for bone and bone marrow specimens or cell blocks.
Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen dependent. Best practice is for paraffin sections to be cut within 6 weeks.
Clinical Reference
1. Kubota Y, Kawazoe A, Mishima S, et al. Comprehensive clinical and molecular characterization of claudin 18.2 expression in advanced gastric or gastroesophageal junction cancer. ESMO Open. 2023;8(1):100762
2. Cao W, Xing H, Li Y, et Al. Claudin18.2 is a novel molecular biomarker for tumor-targeted immunotherapy. Biomark Res. 2022;10(1):38
3. Pellino A, Brignola S, Riello E, et al. Association of CLDN18 protein expression with clinicopathological features and prognosis in advanced gastric and gastroesophageal junction adenocarcinomas. J Pers Med. 2021;11(11):1095
4. Arnold A, Daum S, von Winterfeld M, et al. Prognostic impact of Claudin 18.2 in gastric and esophageal adenocarcinomas. Clin Transl Oncol. 2020;22(12):2357-2363
Method Description
Immunoperoxidase staining and detection of Claudin 18 (CLDN18) is performed in formalin-fixed, paraffin-embedded tissue sections using the VENTANA CLDN18 (43-14A) RxDx Assay. The 4-micron tissue sections are deparaffinized, subjected to heat-induced antigen retrieval and peroxidase inhibitor, incubated with a monoclonal antibody (clone 43-14A), and visualized using a proprietary kit detection system. Sections are counterstained with hematoxylin. Stained slides are examined microscopically by the consulting anatomic pathologist.(Package insert: VENTANA CLDN18 (43-14A) RxDx Assay. Ventana Medical Systems, Inc.; 1016387US Rev A, 10/11/2024)
Results are interpreted using the manufacturer-provided interpretation guide.(Instruction manual: VENTANA CLDN18 (43-14A) RxDx Assay Interpretation Guide for Gastric Adenocarcinoma including Gastroesophageal Junction (GEJ). Ventana Medical Systems, Inc.; 1021576EN Rev B, 10/01/2024)
Day(s) Performed
Monday through Friday
Report Available
5 to 7 daysSpecimen Retention Time
Until reportedPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
88360
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CLD18 | CLDN18, SemiQuant IHC, Manual | 105011-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 620666 | Interpretation | 50595-8 |
| 621004 | Participated in the Interpretation | No LOINC Needed |
| 621005 | Report electronically signed by | 19139-5 |
| 621006 | Material Received | 81178-6 |
| 621007 | Disclaimer | 62364-5 |
| 621008 | Case Number | 80398-1 |
NY State Approved
YesForms
If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.