Polymyalgia rheumatica laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]

Polymyalgia rheumatica (PMR) is a clinical diagnosis that is supported by laboratory tests. Elevation of C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR) is essential for the diagnosis of PMR.

• The following laboratory findings are characteristic of PMR:^[1]
  • Elevated C-reactive protein (CRP)
  • Elevated erythrocyte sedimentation rate (ESR)
  • Absence of rheumatoid factor (RF)
  • Absence of anti-citrullinated protein antibody (ACPA)

• Other supporting laboratory findings are:^[2]
  • Mild normochromic, normocytic anemia (during active phase)
  • Normal white blood cell (WBC)
  • Elevated platelet count
  • Negative antinuclear antibody (ANA)
  • Elevated alkaline phosphatase (detected in one third to half of patients with PMR associated with GCA)
  • Normal creatine kinase (CK)
  • Normal aldolase