ESR depends on -

Ans. is 'd' i.e., All of the aboveErythrocyte sedimentation rate (ESR) o ESR also called Biernacki reaction is the rate at which red cells precipitate in a period of 1 hour.o When anticoagulated blood is allowed to stand undisturbed in veical tube, the red cells tend to fall to the bottom forming two layers -i) Lower red cells layerii) The upper plasma layero This occur in three stages : ?Stage of aggregationo The red cell form rouleux.o This is the most impoant stage and factors which affect this stage markedly after sedimentation rate.Stage of sedimentationo The larger the aggregates formed in stage 1, the faster the rate of fall .Stage fo packingo The individual cells and aggregates slow down due to crowding.The rate at which the RBCs fall is measured and repoed in mm/hr, which is the value of ESR. o Fibrinogen in blood causes RBCs to stick to each other and there by fasten the rouleux formation T ESR. o When viscocity is increased, e.g., in polycythemia, ESR is decreased due to jostling. (or pushing one another)effect on the cells.Methods of ESR estimation 1. Wintrobe:s method oxalate is used as an anticoagulant.2. Westergren's method --> Sodium citrate is used as an anticoagulant.3. Now a days automated analyzer is the method of choice for ESR estimation.