Which lab study findings are associated with polyarteritis nodosa (PAN)?

Updated: Nov 14, 2017
  • Author: Dana Jacobs-Kosmin, MD, FACP; Chief Editor: Herbert S Diamond, MD  more...
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Answer

Laboratory findings in PAN are nonspecific but can help to establish the systemic nature of the disease. Findings include the following:

  • Elevated erythrocyte sedimentation rate (ESR) and/or C-reactive protein - These markers may be useful in evaluating some patients for active disease but do not correlate with activity in all patients [6]

  • Leukocytosis, normochromic anemia, or thrombocytosis

  • Hepatitis B surface antigen and hepatitic C serologies

  • Elevated creatinine level

  • Mild proteinuria

  • Elevated levels of liver enzymes

  • Hypergammaglobulinemia - Found in 30% of patients with PAN

Cryoglobulins, circulating immune complexes, and decreased levels of serum complement (ie, C3, C4) may be observed in patients with HBV-related PAN but are otherwise uncharacteristic of idiopathic PAN.

Cerebrospinal fluid findings often are usually normal in PAN, but polymorphonuclear pleocytosis can be seen when meningeal signs are present.

ANCA testing is rarely positive in PAN. If ANCA testing is positive, the tests more commonly show a perinuclear (rather than cytoplasmic) pattern and antibodies to proteinase-3 and myeloperoxidase will be negative. [6] Antinuclear antibodies and rheumatoid factor are generally negative, but low positive titers may be detected. [6]


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