The Martius Scarlet Blue (MSB) stain kit is intended for use in the histological demonstration of fibrin, muscle, collagen, and erythrocytes. MSB is a reliable method of differentiating fresh and old fibrin clusters.

Fibrin: Red (fresh fibrin may stain yellow and old fibrin blue)
Muscle: Pink to Pale Red
Erythrocytes: Yellow
Nuclei: Red to Black
Collagen: Blue
Other Connective Tissue: Blue