From the Guidelines
Erythrocyte sedimentation rate (ESR) levels are typically markedly elevated in patients with giant cell arteritis (GCA), usually exceeding 50 mm/hour and often reaching 70-100 mm/hour or higher. This elevation occurs because GCA causes significant systemic inflammation, leading to increased production of acute phase proteins like fibrinogen that cause red blood cells to stack together and settle more quickly in the test tube. While ESR is a sensitive marker for GCA, with elevated levels in approximately 80-90% of patients, it's essential to note that normal ESR values (particularly below 40 mm/hour) don't completely rule out GCA. ESR should be used alongside clinical symptoms and other laboratory tests like C-reactive protein (CRP) for diagnosis. During treatment with corticosteroids, ESR levels typically decrease rapidly and can be monitored to assess treatment response, though they shouldn't be the sole criterion for adjusting therapy. Age and gender can influence normal ESR values, with higher baseline levels in elderly patients, so interpretation should consider these factors when evaluating patients with suspected GCA, as suggested by recent guidelines 1. Some key points to consider when interpreting ESR levels in GCA include:
- Elevated ESR levels are common in GCA, but normal levels do not exclude the diagnosis
- ESR should be used in conjunction with clinical symptoms and other laboratory tests for diagnosis
- ESR levels can be monitored to assess treatment response, but should not be the sole criterion for adjusting therapy
- Age and gender can influence normal ESR values, and interpretation should consider these factors. Given the most recent evidence from 2021, the use of ESR as a diagnostic and monitoring tool in GCA is supported by the American College of Rheumatology/Vasculitis Foundation guideline for the management of giant cell arteritis and Takayasu arteritis 1.
From the Research
ESR Levels in Giant Cell Arteritis
- ESR levels are commonly elevated in Giant Cell Arteritis (GCA), with most patients having an ESR >50 mm/h 2, 3, 4.
- However, some studies have reported cases of GCA with ESR levels <50 mm/h, ranging from 27 mm/h to 43.1 +/- 4.9 mm/h 2, 3.
- One study suggested that an ESR > or = 30 mm/h could be used as a laboratory parameter to consider the possibility of GCA, rather than the traditional cutoff of >50 mm/h 3.
- Another study found that the median ESR value was 33 [18-56] in patients with placebo and 26 [15-44] in patients with methotrexate (MTX) 5.
- A case report described a patient with biopsy-proven GCA who had normal ESR and CRP levels at diagnosis, highlighting the importance of clinical suspicion and biopsy confirmation 6.
Variability in ESR Levels
- ESR levels can vary widely in patients with GCA, and may not always be elevated 2, 3, 6.
- Some patients may have normal ESR levels, while others may have elevated levels 3, 5.
- The use of MTX may be associated with lower ESR levels compared to placebo 5.