What is the role of lab tests in the diagnosis of Henoch-Schönlein purpura (IgA vasculitis)?

Updated: Oct 28, 2020
  • Author: Rajendra Bhimma, MBChB, MD, PhD, DCH (SA), FCP(Paeds)(SA), MMed(Natal); Chief Editor: Craig B Langman, MD  more...
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Answer

No specific diagnostic laboratory test is available to assess for markers of IgAV. The following general laboratory tests may be helpful for excluding other diagnoses and evaluating kidney function:

  • Antinuclear antibody (ANA) and rheumatoid factor (RF)
  • Factors VIII and XIII
  • Urinalysis (may show dysmorphic red blood cells and casts with an elevated protein:creatinine ratio)
  • Complete blood count (CBC)
  • Platelet count
  • Erythrocyte sedimentation rate (ESR)
  • Stool guaiac test
  • Blood urea nitrogen (BUN) and creatinine
  • Amylase and lipase
  • Electrolytes
  • Plasma D-dimer
  • Plasma thrombin-antithrombin (TAT) complex, prothrombin fragment (PF)-1, and PF-2
  • Prothrombin time (PT) and activated partial thromboplastin time (aPTT)
  • Serum IgA (elevated in 50-70% of patients with IgAV; higher levels are associated with kidney involvement)
  • Antistreptolysin O (ASO)
  • CH50
  • C3 and C4
  • Immunocomplexes of IgG and IgA

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