Elle2:
Not sure how many replies you may get as this site is primarily dealing with Pulmonary Hypertension in its five groups.
However, a few members do have Limited Systemic Sclerosis (Scleroderma) which is the underlying cause of our Pulmonary Arterial Hypertension.
I am one of them diagnosed 12.5 years ago and received a diagnosis of PAH at the same time.
The primary tests I had at the time were complete blood work up which included ANA tests for antibodies and also tests for inflammatory markers. Visual signs of Scleroderma were also observed at the time, very prominent Telangiectasia (red spots on my face, arms and neck/chest) being one of them. "Sausage" shaped fingers on my right hand......puffiness. Nail fold Capillariscopy looking for irregular patterns in blood vessels....."brocolli" patterns as my Rheumatologist called them. She also checked for skin tightening on my arms and legs primarily. So I was checked for many different things. Of course also a conversation about Raynaud's Phenomenon which I had been diagnosed with 20 years prior to this.
So, the results of all these tests confirmed that I indeed did have Limited Systemic Sclerosis. At the same time I had 6 minute walk test, Pulmonary Function tests, CT scans, Echocardiogram, VQ tests, Stress test, and a few others including a Right Heart Catheterization that confirmed a diagnosis of Pulmonary Arterial Hypertension. So it was a "double whammy" so to speak.
Not sure if this addresses what you are asking but this was my experience as far as I remember it from 13 years years ago.

****As an aside, everyone who has Scleroderma does not have Raynaud's nor does everyone who has Raynaud's develop Scleroderma.****

I have raynauds, scleroderma, Emphysema and PAH. Raynauds was easy for Dr to diagnose, the scleroderma required blood tests and a really knowledgeable Rhuematologist. The PAH was confirmed with RHC. Hope this helps. I think these conditions all feed off each other.

I had heart surgery 1993, developed asthma then pulmonary fibrosis and PAH mild for now stage 3b kidney failure and now severe anemia
my mother only had Raynaulds lost most of her fingers
since I have majority of organ failure I figured I had Scleroderma Cold sedative then all of major organs, especially my longs & blood vessels have scar tissue from biopsies CAT scans & MRI Thank you I will be talking more to my docs😃

I was diagnosed with Reynauds and then mixed Connective tissue disorder and then PAH after all the usual tests and scans. Telangiectasis also mostly on hands plus some mild lung involvement. Started in 2020 and with medications I have remained stable. Mostly deal with fatigue and SOB. However at 86, it could be a lot worse.