Aggregate
In connection with angiography or PTCA, used to describe a collection of erythrocytes ("money roll" appearance, called rouleaux) or platelets. Rouleaux formation is a normal occurrence in non-moving blood. When blood is mixed with large volumes of well tolerated glucose (sugar) or non-ionic contrast media, aggregates that are visible to the naked eye may form. These aggregates are physically very weak and easily broken up, they disappear and dissolve with minimal mixing. When dissolved, the aggregates do not re-appear. Erythrocyte aggregates do not have any clinical importance. Erythrocyte aggregates must not be confused with clotting.
GE Healthcare Glossary