Erythrocyte sedimentation Rate abbreviated ESR is the rate of sedimentation of red cells.It is a non specific haematological test with values raided in wide range of infections,inflammation,degeneration and malignant conditions mostly associated with changes in blood plasma protein concentration such as fibrinogen,immunoglobulins and acute phase reactants like C-reactive proteins
ESR measurement is also affected in conditions such as anemia,pregnancy,haemoglobinopathies,haemoconcentration and some treatments with inflammatory drugs.
When performing ESR,test result should be interpreted in conjunction to other clinical findings and laboratory test.
Principle of ESR
Based o the sedimentation of red blood cells on a vertically positioned westergren tube for an hour.
- Citrated blood is pipetted in a westergren pipette and vertically position then left undisturbed
- The process start by the aggregation or stacking together of red cells which forms rouleaux then sediment through the plasma.
- All these processes occurs in an hour and readings is obtained by the length of the column of clear plasma above the red cells and is measured in millimetres fall per hour (mm fall /Hour)
Equipment required for ESR test
- Westergren pipette (Clean and Dry capillary type pipette tube)
- ESR stand or rack
- Blood samples in anticoagulant (Sodium citrate anticoagulant)
Types of specimen required for ESR Test
- Venous blood collected in sodium citrate anticoagulant
- Venous blood collected in an EDTA tube then diluted with sodium citrate
Procedure of ESR TEST
- Collect blood sample in a sodium citrate anticoagulant tube (about 4 ml)
- Mix the blood by gently swelling or swinging the tube .Alternatively use a tube rotator
- Remove the cap of the test tube and insert a westergren pipette ensuring it is position vertically.
- Attach a pi-pump to the upper opening of the westergren tube then draw the blood slowly and gently to the Zero mark (0) of the westergren tube avoiding to make air bubbles in the tube.
- Without removing the pi-pump from the westergren pipette,tightly fix the lower opening mouth of the westergren pipette on the ESR stand lower pad making sure there’s no blood leakages.
Note : Westergren pipette is a capillary tube.Once one end is closed,there’s no flow of blood but if both openings are opened,blood will flow.
- Now,making sure the westergren pipette is properly fix on the ESR stand lower pad,carefully remove the pi-pump from the westergren tube and vertically fix the upper opening of the pipette to the upper pad of the ESR stand to close the upper mouth of the westergren pipette.
- Allow the setup to stand vertically upright for exactly one hour the read the level at which the plasma meets the read cells in mm/hour
Reference Range of ESR Result
|Men||Up to 10 mm/Hour|
|Women||Up to 15 mm/Hour|
|Elderly person||Up to 20 mm/Hour|
Factors that can affect the level of ESR
Higher volume of ESR can be obtained during pregnancy,menstruation,puerperium and ESR isn’t significantly raised in typhoid,brucellosis,malaria,acute allergy and peptic ulcer
Note : When performing ESR,test result should be interpreted in conjunction to other clinical findings and laboratory test.
Causes of Raised ESR result
ESR is elevated in Acute and chronic inflammatory conditions infections like
- Acute viral hepatitis
- Pelvic Inflammatory Disease
- Haemolytic Disease of the Newborn
- Bacterial endocarditis
- African trypanosomiasis
- Visceral leishmaniasis
Causes of Low ESR result
- Dengue haemorrhagic fever
- Sickle cells