Test Details
Methodology
Immunohistochemistry
Use
The VENTANA PTEN (SP218) RxDx Assay is a qualitative immunohistochemical assay using rabbit monoclonal anti-PTEN, clone SP218, intended for use in the assessment of PTEN protein in formalin-fixed paraffin embedded (FFPE) prostate adenocarcinoma specimens by light microscopy. It is indicated as a companion diagnostic to aid in identifying patients who may be eligible for treatment with TRUQAP (capivasertib) in combination with abiraterone acetate in accordance with the approved therapeutic product labeling.
Special Instructions
Testing will be delayed if the pathology report is not received.
Note: This test number is used for tracking oncology IHC specimens to the laboratory. Bill codes will be added when testing is complete, based on the processes performed in the laboratory.
Limitations
Tissue staining is dependent on the handling and processing of the tissue before staining. Improper fixation, freezing, thawing, washing, drying, heating, sectioning or contamination with other tissues or fluids may produce artifacts, antibody trapping or false negative results. Inconsistent results may result from variations in fixation and embedding methods or from inherent irregularities within the tissue.
Patient specimens collected as fine needle aspirates (FNA) are not recommended.
The recommended tissue fixative is 10% neutral-buffered formalin. Use of PREFER fixative, alcohol-formalin-acetic (AFA), or alcoholic fixatives is not recommended.
The recommended tissue fixation time is for at least six hours and for a maximum of 72 hours. Sections should be cut approximately 4 μm thick and mounted on positively-charged glass slides.
Specimen Requirements
Specimen
Formalin-fixed, paraffin-embedded (FFPE) tissue block or slides
Volume
5 unstained charged slides or paraffin block
Minimum Volume
3 unstained, positively charged slides
Container
Paraffin block or unstained, positive-charged slides
Collection Instructions
Tissue should be fixed in 10% neutral-buffered formalin for six to 72 hours. Embed in paraffin. Slides should be no more than one month old.
Storage Instructions
Room temperature
Causes for Rejection
Insufficient tumor; tumor other than prostate adenocarcinoma; slides sectioned more than one month prior to test request
References
VENTANA PTEN (SP218) RxDx Assay Interpretation Guide. February 10, 2026.
VENTANA PTEN (SP218) RxDx Rabbit Monoclonal Primary Antibody [package insert]. February 10, 2026.