Erythrocyte sedimentation rate ESR. Relevance of ESR in diagnosis of diseases.
Erythrocyte sedimentation rate is a hematological test which measures the rate at which the blood cells sediment and settle down against the gravity when placed in a graduated standard ESR glass tube, placed vertically. The blood sample is treated with anticoagulants like EDTA or oxalate so that it does not form a blood clot during the test.
Measuring ESR in pathology lab.
ESR is measured as mm of the length of the graduated tube which is the distance covered by the falling blood cells in one hour. After withdrawal of blood it is placed in ESR tubes, and ESR tubes are placed vertically. Initially 10 to 15 minutes the RBCs form Rouleaux (singular is Rouleau) where blood corpuscles get staked one up on other or side by side to form a group. The more inflammation in the body the more is the fibrinogen produced in the blood. Fibrinogen reduces the property of blood corpuscles to float freely and facilitate their agglomerate formation. Due to which the red blood corpuscles settle in the ESR tube faster. In normal individual blood cells form Rouleaux very slowly, because the blood cell wall is negatively charged due to presence of Sialic acid in the cell wall, and does not allow the formation of Rouleaux easily.
Blood consists of plasma and red blood cells, the thickness of the plasma depends up on the disease condition and inflammation, and the sedimentation of the erythrocytes depends on the size of the cells and the viscosity and constitution of the plasma, which in turn is marker of the presence of disease like infections, which cause formation of agglomerates of erythrocytes which settle faster in the bold. While some diseases cause plasm a thick and the cells sedimentation rate is decreased. For example the increase in ESR is also one of primary indications that a patient is likely to have infectious disease like tuberculosis.
Some disease symptoms along with Increased ESR values are key elements in diagnosis of a disease Example, Erythematosus Lupus. Rheumatoid Arthritis.
Relation of Erythrocyte sedimentation rate ESR with age and sex of the patient.
ESR increases as the age increases. Old aged patients exhibit high ESR value. Newborn infants have ESR equal to zero and after 5 to 8 days it increases to 2 to 3 mm/hour.
Female patients also have higher values of ESR compared to the same age group than normal male individuals.Therefore, for calculation of ESR the factor for age and sex is considered.
Increase in Erythrocyte sedimentation rate is observed if a person has an inflammatory condition.
In following diseases ESR is increased.
Inflammatory bowel disease
Some types of cancer.
Chronic Kidney Diseases.
Tuberculosis associated anemia.
ESR is decreased in following diseases.
Sickle cell disease (SCD).
Leukocytosis Hepatic disease. Chronic fatigue syndrome.
Methods for measuring Erythrocyte Sedimentation Rate.
1) Wintrobes method:
2) Westergren’s method
3) Microsedimentation method.
4) Zeta sedimentation ratio.