Clumping factor A

Clumping factor A, or ClfA, is a virulence factor from "Staphylococcus aureus" ("S. aureus") that binds to fibrinogen.
ClfA also has been shown to bind to complement regulator I protein.
It is responsible for the clumping of blood plasma observed when adding "S. aureus" to human plasma. Clumping factor can be detected by the slide test.