You can fine the SSDI guidelines on the Social Security web site. They use volume blown in a spirometry test.

Jean

I became eligible when I went on oxygen 24/7 and could no longer work.

I had to retire when I went on oxygen while ambulatory. [No oxygen tanks on job sites.] When I applied for SS disability. I got approved in now months not 6 like it normally takes. They told me I could/should have gotten on 2 years earlier. They consider "Severe COPD" the determining factor.

Helps to have copies of all your records and tests.

They go by your lung functions study. They have to have a statement from at least 2 doctors.

Been waiting in April for 2 years On oxygen CPAP and nebulizers Also have a lawyer Lung function test was bad Also have 2 other SSDI guidelines disabilities besides COPD