Cell Counting  > Consumables & Accessories  > Cell Counting Reagents
Fluorescein Diacetate/Propidium Iodide Stain (FDA/PI Stain)

FDA/PI Stain is a combination of fluorescent dyes for assessing the viability of diverse cell types including mammalian cells, yeast, and pollen grains. FDA is a non-fluorescent dye that permeates cell membranes, undergoing hydrolysis by the esterase activity of viable cells and producing the green fluorescent compound fluorescein. FDA can be retained in viable cells with intact membranes, acting as a live cell marker. PI, a red membrane-impermeable dye, selectively penetrates dead or damaged cells with compromised membranes. PI is a commonly used dead cell marker binding to DNA and RNA through intercalation. Upon binding, a fluorescence intensity of PI can be increased by 20- to 30- fold higher.

Compatible Instruments
LUNA-FL™ Automated Cell Counter
LUNA-II YF™ Automated Yeast Cell Counter
LUNA-FX7™ Automated Cell Counter


Fluorescein Diacetate Stain
Molecular formulaC24H16O7
Molecular weight416.38 g/mol
AppearanceClear liquid
Cell permeabilityMembrane permeant
Excitation/emission494/521 nm (when converted to fluorescein)
Quantity1 x 0.5 mL
Storage-20°C in the dark


Propidium Iodide Stain
Molecular formulaC27H34I2N4
Molecular weight668.39 g/mol
AppearanceClear liquid
Cell permeabilityMembrane permeant
Excitation/emission493/636 nm (in aqueous solution)
533/617 nm (when bound to nucleic acids)
Quantity1 x 0.5 mL
Storage4°C in the dark

Ordering Information

Cat #DescriptionQty
F23214Fluorescein Diacetate/Propidium Iodide Stain2 x 0.5 ml
F23215Fluorescein Diacetate/Propidium Iodide Stain, Sterile-filtered2 x 0.5 ml