Overview

The PD-L1 IHC 22C3 assay, performed on the Dako Autostainer platform, is a widely used companion diagnostic for assessing PD-L1 protein expression by tumor proportion score. For procurement teams and reference labs, ordering this assay involves more than selecting a test name; sample preparation, platform availability, and reporting format all shape the result. This article covers the practical sourcing points buyers should confirm before placing an order.

Confirming Platform and Assay Fit

Because 22C3 is tied to a specific staining platform and antibody clone, the performing laboratory must have the validated Dako workflow. Buyers should confirm the lab runs 22C3 specifically rather than a comparable but distinct PD-L1 assay, since scoring systems and intended therapy associations differ between clones. Matching the assay to the clinical question prevents downstream reinterpretation.

Sample Submission Requirements

The assay is designed for FFPE tumor tissue. Submitting unstained slides with adequate tumor content and proper fixation history supports accurate scoring; poorly fixed or scant samples can yield indeterminate results. Include pathology requisition details such as tumor type and the therapy being considered, because these determine the relevant cut-off and report structure.

Turnaround and Reporting

PD-L1 IHC is generally faster than comprehensive sequencing, often returning within days when the platform is local. Reports state the tumor proportion score and the assay clone used. For cross-border sourcing, confirm that the report format and language meet the receiving clinician's needs and that any courier used preserves sample integrity during transit.

Buyers should also clarify result ownership and data handling before ordering. Some service models return only the scored slide and a short report, while others provide digital images and raw scoring data that the requesting clinician can archive. Agreeing on these details up front avoids rework if the case later moves to a multidisciplinary review. For recurring volume, negotiating batch scheduling with the performing lab can also stabilize turnaround against platform maintenance windows and protect the sample-to-answer timeline.

FAQ

Q: What platform runs the 22C3 assay? A: It is performed on the Dako Autostainer using the 22C3 antibody clone, so the lab must operate that validated workflow.

Q: What sample is required? A: Formalin-fixed, paraffin-embedded tumor tissue with sufficient tumor content and documented fixation is standard.

Q: How quickly are results available? A: IHC is typically faster than NGS, often within days when the staining platform is on-site.

Q: Does 22C3 equal SP263? A: They are different clones on different platforms; studies show strong concordance, but scoring and intended use differ, so the right assay must be chosen deliberately. Documenting the assay clone on both the request and the report prevents later confusion when a case is reviewed across sites or over time.