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Tests

The goals with testing for PSS include diagnosing the condition, distinguishing between different types, evaluating its severity and the degree of organ involvement, detecting complications, and monitoring the condition over time. The diagnosis is largely based upon clinical signs, with specific laboratory testing ordered to help confirm or rule out PSS and more routine or general testing used to help evaluate the person's health status. When the symptoms and test results are characteristic, diagnosing the condition may be relatively straightforward. In many cases, however, symptoms emerge slowly and can initially be mistaken for other conditions.

Laboratory tests

The primary tests performed to help diagnose PSS are autoantibodies. They include:

  • Antinuclear antibodies (ANA) – Positive with a variety of connective tissue and autoimmune disorders. Those with PSS typically have a speckled, nucleolar, or centromere pattern test result.
  • Scl-70 Antibody (Scleroderma Antibody, Anti-topoisomerase Antibody) – Positive in up to 60 per cent of those with PSS.
  • Centromere antibody/centromere pattern – Present in 60-80 per cent of people with limited cutaneous PSS and strongly associated with CREST.
  • RNA POLIII antibody associated with a nucleolar ANA and with renal involvement and disease  severity.

Rarely, a biopsy may be performed to evaluate fibrosis in affected tissue.

Routine testing to help monitor a person's general health status may include:

  • Full Blood Count (FBC) – to evaluate red and white blood cells
  • E/LFTs – to evaluate organ function and chemical and electrolyte balances
  • Nt-Pro BNP –  to screen for pulmonary hypertension
Non-laboratory tests
  • Lung function tests may be performed when lung involvement is suspected. 
  • CT (Computed Tomography) scans may be performed to evaluate lung damage. 
  • X-rays may be done to detect calcium deposits and evaluate lungs. 
  • Cardiac testing and monitoring may be performed when heart involvement is suspected.

Last Review Date: January 13, 2020