what is sed rate in blood

{"title":"Black Top Sodium Citrate Buffer Vacuum Blood Sedimentation Tube 1ml - 6ml","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/ca\/1a\/e87145dece996aa4df6dc4e1de70-200x200-1.jpg","attrs":{"Price":"usd 0.2-0.4\/pcs","Brand Name":"CIPING","Model Number":"CP-4NC","Minimum Order Quantity":"10000pcs","Delivery Time":"10-30days","Certification":"CE, ISO13485","Place of Origin":"China","Payment Terms":"L\/C, D\/A, D\/P, T\/T, Western Union, MoneyGram","Supply Ability":"33000000 Piece\/Pieces per Month","Packaging Details":"100PCS*12\/100PCS*18 in one shipping carton","Color":"Black","Material":"PP, PET, glass","Specimen":"Whole blood","Draw Volume":"1ml-6ml","Sizes":"13x75mm, 7.9x120mm","Origin":"Zhejiang Province, China","Application":"Specially used for blood sedimentation rate test by 'Westergren sedimentation'"}}