Krome Orange has excitation and emission maxima of 398 nm and 528 nm respectively and provides a brighter signal than Pacific Orange* conjugates with equivalent spectral overlaps into adjacent channels.  The new dye is at least as bright as V500 and can provide more than twice the population separation obtained with Pacific Orange dye conjugates, with little compensation compared to Pacific Blue* dye.

Krome Orange conjugates show optimal performance with violet laser excitation and a 550/40 bandpass filter (the standard FL10 channel on flow cytometry systems), while no excitation is detected using a 488 nm laser.  The initial release of Krome Orange includes conjugates to human CD45 and CD4, with the range of human and mouse targets to expand going forward.

“Krome Orange provides scientists with the ability to increase sensitivity for low fluorescence signals and to expand their flexibility for multi-color flow cytometry experiments,” said Brad Calvin, vice president and general manager of the Beckman Coulter Flow Cytometry Business Center.  “The development of this new dye underscores Beckman Coulter’s commitment to expand multi-color cellular analysis technologies.”


About Beckman Coulter

Beckman Coulter, Inc., based in Orange County, California, develops, manufactures and markets products that simplify, automate and innovate complex biomedical tests.  This year marks the company’s 75th anniversary of advancing healthcare.  More than 200,000 Beckman Coulter systems operate in laboratories around the world, supplying critical information for improving patient health and reducing the cost of care.  Recurring revenue, consisting of consumable supplies (including reagent test kits), service and operating-type lease payments, represents about 80 percent of the company's 2009 revenue of $3.3 billion.  For more information, visit or


Photo Caption: Krome Orange dye excitation curve (dashed black line); emission curves for Krome Orange dye, Pacific Orange dye, AmCyan, and V500 dye.  The shaded region represents the standard 550/40 bandpass filter installed into FL10 on a cytometer.