Diagnosis of Vasculitis

Blood tests. An increase in erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels and platelet levels, and a low haemoglobin level (anaemia) are usually common to all forms of vasculitis. Kidney alterations (increased creatine and/or the presence of red blood cells and proteins in the urine) occur with more frequency in small-vessel vasculitides.

Autoimmune markers. Tests for the presence of antineutrophil cytoplasmic antibodies (ANCAs), rheumatoid factor (RF) and cryoglobulins. Other antibodies, such as antinuclear (ANA) and antiDNA antibodies, can be detected in vasculitides associated with other autoimmune diseases.

Imaging tests. Radiological vascular changes indicative of arterial inflammation such as thickening of the vessel wall with reduced blood flow (or stenosis), dilatations (aneurysms) and ruptured blood vessels, which normally occur in medium- and large-vessel vasculitides (e.g., GCA, TKA, PAN and KD). They can be detected through specific tests such as CT-angiography (computed tomography or CT scan), MR-angiography (magnetic resonance), PET (positron emission tomography) or arteriography (performed using an arterial catheter).

Biopsies of different tissues. This test verifies the inflammation of the blood vessel. The biopsy used to diagnose giant cell arteritis (GCA) is carried out on the temporal artery. Polyarteritis nodosa (PAN) is usually diagnosed by means of a biopsy on a skin, muscle or peripheral nerve sample (in addition to an arteriography). Small-vessel vasculitides can also be diagnosed through biopsies of the kidney or lung tissue or with samples from the ears, nose or throat.