Overview

Not every lung cancer patient benefits equally from checkpoint inhibition, so selecting the right population is essential to avoid both undertreatment and unnecessary immune toxicity. The 28-8 PD-L1 assay stratifies non-small cell lung cancer by Tumor Proportion Score, placing each case into a high, low, or negative expression group that maps to different treatment expectations and different regimen choices.

How It Works

The 28-8 mouse monoclonal antibody is applied by immunohistochemistry and scored as the percentage of viable tumor cells with membrane staining. Because the clone was validated against specific therapy thresholds, the reported Tumor Proportion Score can be compared directly to the labeled cutoffs, such as one percent or fifty percent. Automated staining limits operator variability, and the score is confirmed by a pathologist before release so the final number reflects both machine and human review.

Indications

This assay is indicated for advanced non-small cell lung cancer where PD-L1 status guides first-line or subsequent immunotherapy. It is especially valuable when the team must decide between chemo-immunotherapy and chemotherapy alone based on expression level. Patients with higher scores generally fall into the population most likely to gain from single-agent checkpoint blockade, while lower scores may still benefit from a combined chemo-immune approach. For patients near a cutoff, the report notes the confidence interval so the team can discuss borderline cases rather than treating the percentage as an absolute value.

Specimen & Turnaround

A single unstained FFPE slide or a small block is submitted, and staining completes within five to seven business days. The report states the exact percentage so the cutoff comparison is transparent and can be audited later if needed.

Storage & Logistics

Kits travel with validated packaging, and the service supports recurring orders from thoracic networks that test PD-L1 at scale. Each shipment includes a control summary so results remain comparable across batches and across affiliated laboratory sites.

FAQ

Q: What do the 28-8 score thresholds mean? A: They split patients into negative, low, and high PD-L1 groups, each linked to different expected benefit from immunotherapy.

Q: Is 28-8 interchangeable with other PD-L1 clones? A: No, each clone has its own validation and cutoffs, so the result must be read against the 28-8 label it was built for.

Q: How long until the TPS report is ready? A: Most cases are reported within five to seven business days after the slide is received.