Sedimentation reaction
The erythrocyte sedimentation rate BSR abbreviated as - blood cell sedimentation rate , erythrocyte sedimentation (BKS), erythrocyte sedimentation rate , sedimentation rate (SR), erythrocyte sedimentation rate (ESR) or erythrocyte sedimentation rate or blood sedimentation rate designated (BSG) - is the speed with which sinkfähige components of the blood (in an hour ) decrease. It is a non-specific search procedure if there is a suspicion of inflammatory diseases or a laboratory test to assess their progress. Inflammatory diseases in which the rate of sedimentation plays a major role in the assessment are, for example, autoimmune diseases from the rheumatic type , sepsis, or chronic inflammatory bowel diseases (IBD) such as Crohn's disease or ulcerative colitis . An abnormal ESR can also be a sign of diseases of unexplained cause such as sarcoid .
Discovery and development
The Polish pathologist Edmund Biernacki discovered the phenomenon of blood sedimentation in 1897. In 1921 the Swedish pathologists Robin Fåhræus and Alf Westergren further refined the measurement by adding sodium citrate.
Determination method
The determination is usually carried out according to the Westergren method : 1.6 ml of whole blood are made incoagulable with 0.4 ml of 3.8 percent sodium citrate solution (the addition of sodium citrate leads to the binding of the calcium ions necessary for the coagulation process, → citrated blood ) and in Vertical glass or plastic tube with millimeter graduation drawn up to a height of 200 mm. The cellular components of the blood sink ("sediment") downwards and their "lowering" - the length of the cell-free column of blood plasma - is read after one hour, sometimes also after two hours, sometimes even a third value after 24 hours certainly. In the case of a certain value of 5 mm in the first hour and 12 mm in the second one speaks of "5 to 12". The BSR should be carried out at room temperature no later than two hours after the blood sample has been taken.
The specific gravity of erythrocytes (1.096) is higher than that of plasma (1.027). This is the reason why they slowly sink in the stagnant blood that has been rendered incoagulable. An increase in this reduction occurs primarily with inflammation and increased tissue breakdown. The reason for this is the increased tendency of the erythrocytes to aggregate into larger aggregates. The erythrocytes are negatively charged in whole blood, which means that they tend to repel each other and sedimentation takes place relatively slowly. However, if there is an inflammation, so raise z. B. the acute phase proteins partially reduce the negative charge of the erythrocytes and they sediment faster. Since these agglomerates have an overall smaller surface area than the respective individual cells of the same volume, their flow resistance decreases, which leads to a faster sinking and thus to an increase in the ESR.
The ESR is mainly influenced by the composition of the plasma proteins. An increase in albumin reduces the decrease; an increase in fibrinogen , immunoglobulins and acute phase proteins accelerates it. The individual effects of those plasma components on the ESR are additive. Plasma proteins that accelerate ESR are also known as agglomerins. So there is an opposite effect of albumin and globulin on the ESR. An increase in ESR is therefore often accompanied by a shift in the albumin / globulin quotient in the direction of the globulin.
A strong reduction in hematocrit also leads to an increase in ESR due to the reduction in blood viscosity . An increase in cell density, on the other hand, leads to a decrease. Changes in the shape of the erythrocytes, for example in sickle cell anemia or strong variations in the size of the erythrocytes due to different stages of maturity, for example in pernicious anemia , make agglomeration more difficult and thus reduce ESR. Pharmaceuticals such as salicylates and steroid hormones such as estrogens or glucocorticoids increase ESR.
Normal values
As with hardly any other blood value, the literature information fluctuates over the reference or normal values, in some cases differentiation is made depending on gender and age. If there is no differentiation, the reference value after the first hour is approximately up to 10 mm and for the normal value after the second hour up to approximately 20 mm.
Example of a differentiation
The normal values (from G. Herold: Internal Medicine 2016) for under 50-year-olds are after one hour
- in men: up to 15 mm n. W. (according to Westergren)
- in women: up to 20 mm n. W.
For people over 50:
- in men: up to 20 mm n. W.
- in women: up to 30 mm n. W.
rating
An increased BSR is an indication of acute inflammation and can be used in conjunction with other indications as a diagnostic criterion for various inflammatory diseases and infections. A slowed BSR occurs, for example, in polycythemia . An extreme increase in the ESR is referred to as a fall reduction.
Problems:
- The BSR is only in rare cases (less than 0.1%) the sole indication of an underlying disease .
- There is no explanation for about 5% of all elevated sedimentation values.
- A non-elevated BSR does not rule out inflammatory diseases.
- Taking hormone supplements can speed up the BSR.
- Competitive athletes have a slowed BSR due to a higher hematocrit value.
In contrast to CRP - an acute phase protein , which is also used to assess inflammatory diseases - the BSR covers a wider range of diseases. Above all, a pathological increase in immunoglobulins , immune complexes and other proteins is better captured by the lowering of the blood cells. An even slightly increased BSR in young people should therefore be clarified if there are other indications of an illness.
Sources of error
Various sources of error when determining the BSR are described in the literature. These include too high a temperature (the values are standardized to a temperature of 23 ° C), inclined position of the tubes or the frame and too much sodium citrate. In addition, there are opposing neutralizing blood value fluctuations or factors that contribute to this. Liver diseases can, for example, slow down an ESR in spite of the presence of inflammatory processes and thus simulate a normal blood value; an inflammation-dependent increase and a drug-dependent slowdown (for example with methotrexate ) can offset each other.
literature
- Hans Franke: Clinical laboratory methods. Verlag Walter de Gruyter & Co, Berlin 1952.
- Otto Naegeli: Blood diseases and blood diagnostics . Clinical Hematology Textbook, fourth edition, Springer Verlag, Berlin / Heidelberg 1923.
Web links
- The increased sedimentation reaction (accessed June 17, 2019)
- Comparison of selected blood parameters for suitability in the diagnosis of inflammatory diseases in horses (accessed on June 17, 2019)
- Practice of the natural sciences (accessed June 17, 2019)
