When do you consider genetic testing for autoinflammatory diseases in patients with recurrent pericarditis and fever, particularly when symptoms are highly responsive to IL-1 blockade?

Genetic testing is relatively cheap when compared with our medications and biologics. For example, the Invitae immunodeficiency panel, which I frequently use, is about $200 in out-of-pocket cost last year without insurance, which I tell my patients.

However, in my experience, most of the patients I've seen with recurrent pericarditis didn't have a genetic cause that I found through next-generation sequencing, and they frequently responded very well to interleukin-1 (IL-1) blockade. I've definitely seen adult-onset Still's disease (AoSD) cause recurrent fever and pericarditis.

When patients don't respond to the biologics, I start to worry about mimics (although they are rare). The worst possible misdiagnosis is an aortic valve root endocardi...