(HealthDay News) — Use of pulmonary function tests (PFTs) is associated with high false negative rates for detection of scleroderma-associated interstitial lung disease (SSc-ILD), according to a study published online August 28 in Arthritis & Rheumatology.

Yossra A. Suliman, MD, from the University Hospital Zurich, and colleagues prospectively enrolled 102 SSc patients who were assessed following EUSTAR standards to compare PFTs and high-resolution computed tomography of the chest (HRCT). Two experienced radiologists blindly evaluated the images.

The researchers found that 63% of patients showed significant ILD on HRCT, 26% had a forced vital capacity (FVC) <80%, and 53% had a reduction in one or more PFTs. The false negative rate of FVC was high, with normal FVC in 62.5% of patients with significant ILD on HRCT. Six percent of patients with normal FVC had severe, functionally-occult lung fibrosis; two of these patients had all PFTs within normal limits. Compared with ILD-free cases, false negative cases more often had anti-Scl-70 antibodies and diffuse SSc, and less frequently had anti-centromere antibodies (ACA).

“The derived evidence-based data reveal a high risk of missing the detection of significant SSc-ILD when relying solely on PFTs,” the authors write. “Particularly, additional imaging investigations should be considered in ACA negative patients with normal FVC for the early detection of SSc-ILD.”

Several authors disclosed financial ties to the pharmaceutical industry.

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