ESR
Erythrocyte Sedimentation Rate
What it is
The erythrocyte sedimentation rate (ESR) measures how quickly red blood cells settle to the bottom of a vertical tube of anticoagulated blood over one hour, reported in millimetres per hour (mm/hr). Under normal conditions, red blood cells carry a negative surface charge that causes them to repel each other and settle slowly. When the blood contains elevated concentrations of acute-phase proteins — particularly fibrinogen, immunoglobulins, and C-reactive protein — these coat the red blood cells and neutralise their surface charge, causing them to aggregate into rouleaux (stacks) and settle more rapidly. ESR therefore rises with any condition that elevates acute-phase proteins: systemic inflammation, infection, autoimmune disease, tissue necrosis, and paraproteinaemia. ESR is one of the oldest laboratory tests still in widespread clinical use — simple, inexpensive, and non-specific, but providing clinically important information when placed in context.
Why we measure it
ESR complements hsCRP and IL-6 in the inflammatory picture, but its temporal dynamics are different and clinically informative. hsCRP rises within hours of an inflammatory stimulus and falls rapidly when the stimulus resolves; ESR responds more slowly — it rises over days and remains elevated longer, reflecting the sustained presence of elevated fibrinogen and immunoglobulins that persist after acute hsCRP has normalised. This makes ESR more sensitive for chronic, smouldering inflammatory conditions where the acute-phase response has plateaued at a lower level — including early rheumatoid arthritis, polymyalgia rheumatica (in which ESR is typically markedly elevated and is a diagnostic criterion), vasculitides, and some haematological malignancies. Multiple myeloma produces a paraprotein (monoclonal immunoglobulin) in large quantities — this dramatically elevates ESR, often to values exceeding 100 mm/hr, as immunoglobulin-coated red blood cells sediment rapidly. A markedly elevated ESR (typically > 100 mm/hr) in an otherwise unexplained clinical context is a classic signal for haematological malignancy workup, including serum protein electrophoresis and immunofixation. Annual ESR in the Blueprint Bloodwork provides an annual check on this slow-moving but diagnostically important marker — a counterpart to the quarterly hsCRP that captures fast-moving inflammatory change.
Why every 12 months
Annual testing at the Blueprint Bloodwork draw is appropriate for ESR as a surveillance marker. Unlike hsCRP (measured quarterly), ESR provides a once-yearly snapshot of the chronic inflammatory state. Its slow dynamics mean that meaningful elevation will persist across the annual measurement — a transiently elevated ESR from an acute infection will have normalised by the next annual draw without requiring intervention.
What movement means
ESR reference ranges are age- and sex-dependent. The Westergren method (the standard method) produces upper reference limits of approximately 15 mm/hr for males under 50 and 20 mm/hr for females under 50, rising to 20 mm/hr and 30 mm/hr respectively for those over 50. A commonly used age-adjusted formula is: upper normal ESR = age (in years) / 2 for males; (age + 10) / 2 for females.
Normal
< 15 mm/hr (male < 50) · < 20 mm/hr (female < 50) — rises with age
Within the age- and sex-appropriate reference range. Annual tracking provides trend data that contextualises future readings. Stable normal ESR across annual draws is reassuring regarding chronic inflammatory and haematological conditions.
Westergren reference method — standard laboratory reference ranges vary by age and sex
Mildly Elevated
20 – 50 mm/hr
Mild elevation. Common in chronic infections, early inflammatory arthritis, anaemia, and pregnancy. Clinical context, trend across annual draws, and correlation with hsCRP, ANA, and RF should guide further assessment.
Standard laboratory reference ranges
Significantly Elevated
> 50 mm/hr
Warrants clinical review. Common in active autoimmune disease (RA, SLE, vasculitis, polymyalgia rheumatica), significant infection, and haematological malignancy. ESR above 100 mm/hr — particularly in the absence of overt infection — should prompt serum protein electrophoresis, immunofixation, and haematology review to exclude multiple myeloma.
Sox HC, Liang MH, Annals of Internal Medicine, 1986 — doi:10.7326/0003-4819-104-4-515
References
- 1.
Sox HC, Liang MH. “The Erythrocyte Sedimentation Rate: Guidelines for Rational Use.” Annals of Internal Medicine. 1986.
- 2.
Brigden ML. “Clinical Utility of the Erythrocyte Sedimentation Rate.” American Family Physician. 1999.
- 3.
Salvarani C, Cantini F, Hunder GG. “Polymyalgia Rheumatica and Giant-Cell Arteritis.” The Lancet. 2008.
- 4.
Rajkumar SV, Dimopoulos MA, Palumbo A, et al.. “International Myeloma Working Group Updated Criteria for the Diagnosis of Multiple Myeloma.” The Lancet Oncology. 2014.