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Epic Test 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, Manual

Specimen Type

Special

Specimen 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.

Day(s) Performed

Monday through Friday

Report Available

5 to 7 days

Specimen Retention Time

Until reported

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

88360

NY State Approved

Yes

Forms

If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.