The Classic Inflammation Speedometer
ESR measures how fast red blood cells settle in a tube over one hour. When there's inflammation, proteins like fibrinogen coat red blood cells, making them clump together (rouleaux) and settle faster. It's one of the oldest lab tests and is very nonspecific—almost any inflammation raises ESR. But it's still critical for diagnosing and monitoring temporal arteritis and polymyalgia rheumatica.
What is ESR (Erythrocyte Sedimentation Rate)?
ESR measures the rate of RBC sedimentation in mm/hour (Westergren method). Normal upper limit: age/2 for men, (age+10)/2 for women. Affected by RBC shape, plasma proteins (especially fibrinogen), and hematocrit. Slower to rise and fall than CRP.
↑ What High ESR (Erythrocyte Sedimentation Rate) Means
Inflammation somewhere. Very nonspecific—infections, autoimmune disease, cancer, pregnancy, anemia, and aging all raise ESR. Very high ESR (>100) narrows the differential: infection, malignancy (especially myeloma), autoimmune disease, or temporal arteritis.
Common symptoms:
Depends entirely on cause · If temporal arteritis: new headache, scalp tenderness, jaw claudication, vision changes (EMERGENCY) · If PMR: bilateral shoulder/hip stiffness and pain, morning stiffness · If infection: fever, malaise, organ-specific symptoms
↓ What Low ESR (Erythrocyte Sedimentation Rate) Means
Polycythemia, sickle cell disease, and extreme leukocytosis can lower ESR.
Common symptoms:
Polycythemia symptoms if from high hematocrit
Why It Matters
When normal:
Essential for diagnosing temporal arteritis (ESR typically >50)
Monitors polymyalgia rheumatica treatment
Very high ESR (>100) narrows differential diagnosis
Complements CRP for inflammation monitoring
Risks if abnormal:
Extremely nonspecific
Affected by age, sex, anemia, and many non-inflammatory factors
Slower to respond than CRP (rises and falls over days-weeks)
What Can Cause Abnormal Levels?
Infection
35% likelyMost infections raise ESR. Osteomyelitis and endocarditis classically have very high ESR.
Autoimmune Disease
30% likelyLupus, RA, vasculitis, PMR all elevate ESR.
Malignancy
Lymphoma, myeloma, and metastatic cancer. Myeloma often has very high ESR (>100).
Anemia
Lower hematocrit = faster sedimentation. Anemia alone raises ESR.
Age
ESR increases with age. Use age-adjusted upper limits.
Pregnancy
Elevated fibrinogen in pregnancy raises ESR.
Temporal Arteritis/GCA
Classic: elderly patient with headache, jaw claudication, vision changes, and ESR >50.
What You Can Do
ESR is a diagnostic/monitoring marker, not a lifestyle target
Impact: Treat the underlying cause \u00B7 Timeline: N/A
ESR >100: focused workup for infection, malignancy, autoimmune disease
Impact: Narrows differential significantly \u00B7 Timeline: Urgent
If lifestyle changes aren't enough:
Pair ESR with CRP for inflammation assessment
Impact: CRP is faster and more specific. Discordance can be informative. \u00B7 Timeline: Together
If temporal arteritis suspected: ESR + CRP + urgent ophthalmology
Impact: Vision loss can be permanent if untreated \u00B7 Timeline: URGENT
Recommended retest: Per disease monitoring (GCA/PMR: monthly during taper); not routine screening
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