The Westergren Method determines Erythocryte Sedimentation Rate after 1 hour in a vertically mounted tube of defined length (200 mm) and diameter (2,55 mm). The blood is diluted with a dedicated diluent in a 4:1 ratio.

The objective of ESR testing is to measure inflammability state. The Westergren method measures both infections related to infectious diseases and chronic inflammatory conditions.

The Westergren Method was introduced in 1921 and accepted by the International Council for Standardization in Haematology (ICSH) and the National Committee for Clinical Laboratory Standards as the reference method.

Wikipedia ESR