Estrogen Receptor/Progesterone Receptor (ER/PR) Tests
Reviewed
ER/PR tests check if breast cancer cells have estrogen and/or progesterone receptors. The results help guide treatment by showing whether the cancer is hormone receptor-positive (likely to respond to hormone therapy) or hormone receptor-negative (unlikely to respond).
Preparation and collection
Your provider will give specific instructions. If you take blood thinners (including aspirin), you may need to stop before the biopsy. Tell your provider about all medicines and supplements. If you receive general anesthesia, you will likely need to fast for several hours before the procedure and arrange for someone to drive you home.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- The test is performed on tissue from a breast biopsy; the accuracy depends on the quality and representativeness of the sample.
- Results are interpreted by a pathologist and should be discussed with your healthcare provider, who will consider the full clinical picture.
- False-positive or false-negative results are possible but uncommon; your provider may recommend additional testing if results are unclear.
What to do next
Your provider will use the hormone receptor status along with other test results (such as HER2 status) to create a personalized treatment plan. Ask your provider any questions you have about your results and what they mean for your care.
Evidence source
U.S. National Library of Medicine: Estrogen Receptor/Progesterone Receptor (ER/PR) Tests