Difficulty in blood typing after infusion of plasma substitutes. Relationship to erythrocyte sedimentation rate and rouleaux-formation.

Recently we experienced one incident that the patient with A blood type reacted as AB type on macroscopic observation when the blood type was tested immediately after the infusion with Dextran70 in saline. The patient was confirmed as having the A type by reexamination later. Subsequently 90 cases were subjected to blood typing following infusion with one of the seven plasma substitutes such as dextran, MF-gelatin and HE-starch. One patient demonstrated an abnormal reaction. She had marked acceleration of erythrocyte sedimentation rate (E.S.R.) and positive serological reactions for syphilis before the infusion with Dextran70. It was thought that the rapid increase in high molecular colloids in circulation accelerated rouleaux formation and caused the change in agglutination thus resulted in misjudgement of blood typing.