The goals with testing for scleroderma 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. Diagnosis is largely based upon clinical signs, with specific laboratory testing ordered to help confirm or rule out scleroderma and more routine or general testing used to help evaluate the person's general 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 may initially be mistaken for other conditions.
There is no one laboratory test to diagnose scleroderma. A battery of tests is performed to detect the presence or absence of autoantibodies that are generally associated with the diagnosis of scleroderma. They include:
- Antinuclear antibodies (ANA) – positive with a variety of connective tissue and autoimmune disorders; present in about 95% of those with scleroderma, typically with a speckled, centromere, or – more rarely – nucleolar pattern test result.
- Scl-70 antibody (Scleroderma antibody, Anti-topoisomerase I antibody) – positive and very specific in 20-60% of adults with scleroderma; associated with increased risk of pulmonary fibrosis.
- Centromere antibody (ACA)/centromere pattern – present in 60-80% of those with limited cutaneous scleroderma and strongly associated with CREST and pulmonary hypertension.
- Other, less frequently ordered tests for autoantibodies include anti-fibrillarin (U3RNP), anti-PM/Scl, anti-RNA polymerases I/III, anti-Nor-90, anti-PM-Scl, anti-B23, anti-U1-RNP, AHAs (anti-histone), and anti-Th/To. These tests are not routine and are often referred to a reference laboratory.
General and routine testing that may be ordered to help monitor a person's health status may include:
- Complete blood count (CBC) – to evaluate red and white blood cells
- Comprehensive metabolic panel (CMP) – to evaluate organ function and chemical and electrolyte balances
- Thyroid function 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.