Erythrocyte sedimentation rate

Erythrocyte sedimentation rate
Westergren pipet array on StaRRsed automated ESR analyzer. The ESR is the height (in mm) of the colourless portion at the top of the pipette after one hour.
Synonymssedimentation rate, Westergren ESR, ESR, sed rate[1]
Reference rangeMale: ≤ age/2 ; Female: ≤ (age + 10)/2.[2] (Unit: mm/hour).[2]
PurposeDetection of inflammation in body.[1]
Test ofThe rate of sedimentation of erythrocytes in a vertical tube over an hour.[1]
Based onThe millimeters of transparent fluid present at the top portion of the vertical tube after an hour.[1]
MeSHD001799
MedlinePlus003638
LOINC30341-2

The erythrocyte sedimentation rate (ESR or sed rate) is the rate at which red blood cells in anticoagulated whole blood descend in a standardized tube over a period of one hour. It is a common hematology test, and is a non-specific measure of inflammation. To perform the test, anticoagulated blood is traditionally placed in an upright tube, known as a Westergren tube, and the distance which the red blood cells fall is measured and reported in millimetres at the end of one hour.[3]

Since the introduction of automated analyzers into the clinical laboratory, the ESR test has been automatically performed.

The ESR is influenced by the aggregation of red blood cells: blood plasma proteins, mainly fibrinogen, promote the formation of red cell clusters called rouleaux or larger structures (interconnected rouleaux, irregular clusters). As according to Stokes' law the sedimentation velocity varies like the square of the object's diameter, larger aggregates settle faster. While aggregation already takes place at normal physiological fibrinogen levels, these tend to increase when an inflammatory process is present, leading to increased ESR.

The ESR is increased in inflammation, pregnancy, anemia, autoimmune disorders (such as rheumatoid arthritis and lupus), infections, some kidney diseases and some cancers (such as lymphoma and multiple myeloma). The ESR is decreased in polycythemia, hyperviscosity, sickle cell anemia, leukemia, chronic fatigue syndrome,[4] low plasma protein (due to liver or kidney disease) and congestive heart failure. Although increases in immunoglobulins usually increase the ESR, very high levels can reduce it again due to hyperviscosity of the plasma.[5] This is especially likely with IgM-class paraproteins, and to a lesser extent, IgA-class. The basal ESR is slightly higher in females.[6]

  1. ^ a b c d "Erythrocyte Sedimentation Rate (ESR)". Lab Tests Online. Retrieved 2019-12-23.
  2. ^ a b Miller, A; Green, M; Robinson, D (1983-01-22). "Simple rule for calculating normal erythrocyte sedimentation rate". British Medical Journal (Clinical Research Ed.). 286 (6361). BMJ: 266. doi:10.1136/bmj.286.6361.266. ISSN 0959-8138. PMC 1546487. PMID 6402065.
  3. ^ "Erythrocyte Sedimentation Rate (ESR)". labtestsonline.org. Retrieved 2019-12-12.
  4. ^ Saha, Amit K; Schmidt, Brendan R; Wilhelmy, Julie; Nguyen, Vy; Do, Justin; Suja, Vineeth C; Nemat-Gorgani, Mohsen; Ramasubramanian, Anand K; Davis, Ronald W (2018-11-21). "Erythrocyte Deformability As a Potential Biomarker for Chronic Fatigue Syndrome". Blood. 132 (Suppl 1): 4874. doi:10.1182/blood-2018-99-117260. ISSN 0006-4971. Retrieved 2019-06-19.
  5. ^ Eastham, R. D (1954). "The Erythrocyte Sedimentation Rate and the Plasma Viscosity". Journal of Clinical Pathology. 7 (2): 164–167. doi:10.1136/jcp.7.2.164. PMC 1023757. PMID 13163203.
  6. ^ MedlinePlus Encyclopedia: ESR