ViaCheck™ Viability Control 25% is a suspension of microspheres that simulate dead (or dying) cells stained with Trypan Blue. ViaCheck™ SingleShots™ minimize error and maximize efficiency by circumventing potential human error from repeated bottle resuspension & pipetting steps. BLI25BS is the SingleShot equivalent to 20mL Cat. # 25997. Supplemental ViaCheck™ Literature