How is AERD diagnosed?

There is no specific test to detect AERD. Lab tests that can help in making the diagnosis include a blood test to look for higher than normal levels of white blood cells called eosinophils, and a urine test to look for elevated leukotrienes, inflammatory substances in the body. A clinical diagnosis of AERD can be made if all three of these features are present: asthma, nasal polyps, and respiratory reactions to aspirin and NSAIDs.

When it's not clear whether the person has had a reaction to aspirin or NSAIDs, an aspirin challenge (desensitization) is sometimes done to confirm the diagnosis. Aspirin is given in a safe medical environment where the doctor and health care team follow specific guidelines.