This National Jewish Health (NJH) Investigator Initiated pilot study funded by the Shah Foundation will prospectively perform a non invasive lung function test called Lung Clearance Index (LCI) to determine if 50 scleroderma patients without evidence of lung disease who have evidence of small airway inflammation or impairment to airflow are more likely to develop ILD than those with normal vales.50 subjects will be enrolled from the Rheumatology practice at NJH and followed with phone interviews or Electronic Medical Record (EMR) record review yearly times 5 to determine if they have subsequently developed evidence of ILD or pulmonary artery hypertension.

50 scleroderma patients without evidence of lung disease who have been seen by an NJH Rheumatologist will be invited to participate. They will have their medical records reviewed to determine eligibility and then perform hand held spirometry and LCI testing. This measures evidence of small airway airflow obstruction and requires normal breathing while first on room air followed by inhaling a gas mixture of 100% oxygen. The Oxygen concentration in exhaled breathing and the number of breaths needed to return to room air concentration of Oxygen will be analyzed by a computer. Medical information from the EMR will be recorded and placed in a secure database, REDCap, for statistical analysis to determine if LCI results or other clinical features are predictive of which Scleroderma patients are most likely to subsequently develop evidence of Interstitial Lung disease (ILD) based upon yearly phone call interviews and EMR record reviews within 5 years of baseline testing.

Inclusion Criteria:

• Confirmed diagnosis of systemic sclerosis (SSC) by an NJH Rheumatologist
• age 21-75
• No evidence of Scleroderma related Lung disease (ILD)
• Able to comprehend and sign an Institutional Review Board (IRB) approved consent form.

Exclusion Criteria:

• Patients without a Rheumatologists confirming a diagnosis (DX) of SSC
• Patients with evidence of lung involvement based upon; Thoracic imaging, abnormal Pulmonary Function Tests (PFTs); Forced Vital Capacity( FVC), Forced Expiratory Volume in 1 second (FEV1) or a Diffusion Capacity for Carbon Monoxide (DLCO) < the Lower Limit of Normal (LLN) or Saturation of Oxygen in arterial blood (SaO2) < 90% .
• Cardiac echocardiogram or right heart catheter evidence of Pulmonary Arterial Hypertension (PAH).
• < 21 or > 75 years of age
• Must not be pregnant or had eye surgery within 2 weeks of LCI testing
• Must be able to comprehend and sign an IRB approved consent form and complete LCI testing

Scleroderma patients without lung disease