Erythrocyte Sedimentation Rate in Temporal Arteritis
In temporal arteritis (giant cell arteritis), ESR values typically exceed 40 mm/h, with values above 100 mm/h having the highest specificity (92.2%) for the disease. 1
Diagnostic Value of ESR in Temporal Arteritis
- ESR >40 mm/h has high sensitivity (93.2%) for giant cell arteritis with a negative likelihood ratio of 0.18, making it a valuable screening tool 1, 2
- ESR >50 mm/h has a sensitivity of 78.9% and specificity of 43.5% for giant cell arteritis 1
- ESR >60 mm/h has a sensitivity of 70.7% and specificity of 70.5% with a positive likelihood ratio of 5.77 1
- ESR >80 mm/h has a sensitivity of 50.7% and specificity of 81.8% with a positive likelihood ratio of 4.62 1
- ESR >100 mm/h has the highest specificity (92.2%) with a positive likelihood ratio of 3.11, making it strongly suggestive of temporal arteritis 1, 2
Clinical Interpretation of ESR Values
- A normal ESR should raise suspicion for an alternative diagnosis, as raised inflammatory markers are highly sensitive for temporal arteritis 1
- The mean ESR in patients with temporal arteritis and fever has been reported as 97.0 mm/hr (range 14-149 mm/hr) 3
- In a study of 248 patients with giant cell arteritis, the mean ESR was 96.4 ± 23.6 mm/h in most patients 4
- While rare, temporal arteritis with normal or only mildly elevated ESR (<50 mm/h) has been documented in approximately 4% of cases 4
Factors Affecting ESR in Temporal Arteritis
- Prior steroid therapy can lower the ESR in patients with temporal arteritis, potentially leading to falsely reassuring values 5
- Patients with temporal arteritis and lower ESR (<50 mm/h) tend to have higher hemoglobin levels than those with high ESR 5
- Women typically have higher baseline ESR values than men, which should be considered when interpreting results 2
- Comorbid conditions like nephrotic syndrome or renal insufficiency can cause highly elevated ESR (>100 mm/h), potentially leading to diagnostic confusion 6
Diagnostic Approach
- Due to the possibility of false negative results and the risk of irreversible ocular involvement, high-dose glucocorticoids should be commenced on strong clinical suspicion of giant cell arteritis, even before biopsy confirmation 1
- Temporal artery biopsy remains the gold standard for diagnosis of giant cell arteritis, but should not delay treatment initiation 1
- C-reactive protein (CRP) should also be measured, as a normal ESR or CRP should raise suspicion for an alternative diagnosis 1
- An ESR <30 mm/h makes temporal arteritis unlikely, though rare cases have been reported with normal ESR 7, 4
Clinical Pitfalls
- Relying solely on ESR can lead to missed diagnoses, as approximately 4% of temporal arteritis cases present with ESR <50 mm/h 4
- Patients already on steroid therapy for polymyalgia rheumatica may have artificially lowered ESR values despite active temporal arteritis 5
- Headache (41% vs 75%) and jaw claudication (9% vs 43%) are found less often in patients with temporal arteritis without an elevated ESR compared to those with elevated ESR 7
- Anemia and azotemia can artificially elevate ESR values, potentially leading to false positive suspicion for temporal arteritis 2, 6