In a patient over 50 with typical polymyalgia rheumatica (proximal shoulder‑hip girdle pain and morning stiffness) and no atypical systemic features, is ANCA testing indicated?

ANCA Testing in Typical Polymyalgia Rheumatica

ANCA testing is NOT indicated in patients over 50 with typical polymyalgia rheumatica who present with classic proximal shoulder-hip girdle pain, morning stiffness, and no atypical systemic features. 1

Core Laboratory Workup for Typical PMR

The European League Against Rheumatism recommends a focused baseline laboratory dataset that does not include ANCA testing for straightforward presentations 2, 1:

• Essential inflammatory markers: ESR and/or CRP (typically markedly elevated) 1, 3
• Autoantibody screening: Rheumatoid factor and/or anti-CCP antibodies (to exclude rheumatoid arthritis) 1, 4
• Complete blood count (assess for anemia or other causes of inflammation) 1
• Metabolic panel: Glucose, creatinine, liver function tests (baseline before glucocorticoid therapy) 1
• Bone profile: Calcium, alkaline phosphatase (pre-steroid bone health assessment) 1
• Additional screening: Creatine kinase (should be normal; excludes myositis), TSH, protein electrophoresis, urinalysis 1, 5

When ANCA Testing IS Indicated

ANCA and ANA testing should be reserved for atypical presentations that raise suspicion for vasculitis or other autoimmune conditions 1:

• Age < 60 years (especially < 50 years—mandates specialist referral) 2, 6
• Systemic constitutional symptoms beyond typical PMR (unexplained weight loss, fever, organ involvement) 2
• Peripheral inflammatory arthritis (polyarticular involvement) 2
• Low or normal inflammatory markers despite active symptoms 2, 6
• Lack of response to appropriate glucocorticoid dosing (12.5–25 mg prednisone) within 2 weeks 2, 5
• Clinical features suggesting vasculitis: purpura, neuropathy, renal involvement, or pulmonary symptoms 1

Why ANCA Testing Is Not Routine

In a Japanese cohort of 44 PMR patients, no patient tested positive for ANCA, underscoring its lack of diagnostic utility in typical PMR 7. The condition is diagnosed clinically based on:

• Bilateral shoulder/hip girdle pain and morning stiffness 3, 8
• Age > 50 years (peak incidence ~75 years) 3, 8
• Elevated inflammatory markers (mean CRP often > 8 mg/dL) 7
• Dramatic response to low-dose glucocorticoids (15–25 mg prednisone) within 1–2 weeks 2, 5

Common Pitfall to Avoid

Do not order an extensive autoimmune panel (including ANCA, ANA, or other vasculitis markers) in every patient with suspected PMR, as this leads to false-positive results, unnecessary specialist referrals, and delayed treatment 1. The 2015 EULAR/ACR guidelines explicitly state that serological tests like ANCA are considered only when other autoimmune conditions are suspected based on atypical clinical features 1.

Immediate Next Steps for Your Patient

For a patient over 50 with typical PMR presentation:

1. Order the core laboratory panel (ESR/CRP, RF/anti-CCP, CBC, metabolic panel, CK, TSH) 1, 4
2. Initiate prednisone 15–20 mg daily (within the 12.5–25 mg range) 2
3. Assess response at 1–2 weeks: Expect near-complete resolution of symptoms 2, 5
4. Refer to rheumatology only if atypical features emerge, inadequate response occurs, or frequent relapses develop 2

ANCA testing adds no diagnostic value in this scenario and should be omitted. 1, 7