Erythrocyte sedimentation rate

The erythrocyte sedimentation rate (ESR), also called a sedimentation rate, sed rate or 'Biernacki Reaction', is a non-specific measure of inflammation that is commonly used as a medical screening test.

To perform the test, anticoagulated blood is placed in an upright tube, known as a Westergren tube and the rate at which the red blood cells fall is measured and reported in mm/h.

When an inflammatory process is present, the high proportion of fibrinogen in the blood causes red blood cells to stick to each other. The red cells form stacks called 'rouleaux' which settle faster. Rouleaux formation can also occur in association with some lymphoproliferative disorders in which one or more immunoglobulins are secreted in high amounts. Rouleaux formation is however a physiological finding in some equidae and can be as such in felidae and suidae species, namely the horse, cat and pig respectively.

The ESR is increased by any cause or focus of inflammation. The ESR is decreased in sickle cell anemia, polycythemia, and congestive heart failure. The basal ESR is slightly higher in females.

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History

This test was invented in 1897 by the Polish doctor Edmund Biernacki.^[1] In 1918 the Swedish pathologist Robert Sanno Fåhræus declared the same and along with Alf Vilhelm Albertsson Westergren are eponymously remembered for the Fåhræus-Westergren test (in the UK, usually termed Westergren test),^[2] which uses sodium citrate-anticoagulated specimens.^[3]

Uses

Although it is frequently ordered, the erythrocyte sedimentation rate (ESR) is not a useful screening test. It is only useful for diagnosing three diseases: myeloma, temporal arteritis and polymyalgia rheumatica (in which it may exceed 100 mm/hour).

It is commonly used for a differential diagnosis for Kawasaki's Disease and it may be increased in some chronic infective conditions like tuberculosis and infective endocarditis. It is a component of the PDCAI, an index for assessment of severity of inflammatory bowel disease in children.

The clinical usefulness of erythrocyte sedimentation rate (ESR) is limited to monitoring the response to therapy in certain inflammatory diseases such as temporal arteritis, polymyalgia rheumatica and rheumatoid arthritis. It can also be used as a crude measure of response in Hodgkin's lymphoma. Additionally, ESR levels are used to define one of the several possible "adverse prognostic factors" in the staging of Hodgkin's lymphoma.

The use of the ESR as a screening test in asymptomatic persons is limited by its low sensitivity and specificity. When there is a moderate suspicion of disease, the ESR may have some value as a "sickness index."

An elevated ESR in the absence of other findings should NOT trigger an extensive laboratory or radiographic evaluation.

Normal Values

Note: mm/hr. = millimeters per hour.

Values are increased in states of anemia,^[4] and in black populations.^[5]

Adults

ESR reference ranges from a large study:^[6]

As an alternative the following formula may be used to give predicted values for ESR based on age and gender:^[7]

Children

• Newborn: 0 to 2 mm/hr.
• Neonatal to puberty: 3 to 49 mm/hr.

1. Newborn: 0-5 mm/hr.
2. Neonatal to puberty: 0-15 mm/hr.

See also

• C-reactive protein