PDL1 (Immunotherapy) Tests Test
A PD-L1 test measures how much of a protein called PD-L1 is on your cancer cells. High levels may mean that immunotherapy could help your immune system fight the cancer.
What this test measures
A PD-L1 test uses a sample of cancerous tumor tissue to measure how much of a protein called programmed-death ligand 1 (PD-L1) is found on the cancer cells.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
High levels of PD-L1 may mean that your cancer can be treated with immunotherapy, such as immune checkpoint inhibitors, which help your immune system attack cancer cells.
Lower-than-normal results
Low levels of PD-L1 mean that immunotherapy likely won't help, and your provider will consider other cancer treatments.
Frequently asked questions
What is a PD-L1 test?
It measures how much PD-L1 protein is on your cancer cells to help decide if immunotherapy might work.
How is the test done?
A sample of your cancerous tumor tissue is used to measure PD-L1 levels.
What does a positive result mean?
It means your tumor has enough PD-L1 that you may benefit from immunotherapy medicines like pembrolizumab, nivolumab, or atezolizumab.
What does a negative result mean?
It means your tumor doesn't have enough PD-L1, so immunotherapy likely won't help. Your provider will consider other treatments.
What are CPS and TPS scores?
CPS (Combined Positive Score) measures PD-L1 on tumor cells and T-cells. TPS (Tumor Proportion Score) measures the percentage of tumor cells with high PD-L1. Different tests use different scores.
Related lab tests
Sources
- MedlinePlus: PDL1 (Immunotherapy) Tests — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.