What Is Fluorescein?


Abbey Color is one of a few companies in the world that makes and supplies fluorescein, which is an oil soluble dye. An orange-red powdered compound, it is designated by the formula C20H12O5,that exhibits intense greenish-yellow fluorescence in alkaline solution and is used in medicine for diagnostic purposes, in ophthalmology to reveal corneal lesions, and as a textile dye.


Note: fluorescein is sometimes misspelled as flourescein. (Without spell check, we’d probably do it, too. We’ve got your back.)

What Is Fluorescein Used For?


Typically for medical/laboratory applications:

  • In ophthalmology and optometry, fluorescein is a component in various diagnostic tests, including corneal abrasions and trauma caused by gas permeable contact lenses. Abbey Color is the preferred supplier of fluorescein dye to the optical industry for use in diagnostics for corneal trauma.
  • Fluorescein has also found use as a suitable replacement for luminol for blood detection and crime scene investigations.


The water-soluble form of fluorescein called Uranine is used in oceanography as a tracer.

But I’m Looking for Fluorescein USP. Is that the same thing?


Yes, with more refinement to make it suitable for internal pharma applications. The manufacturing process follows the protocol of United States Pharmacopeia (USP) directives and subsequent testing procedures. Fluorescein USP is sold in lots of of 100 pounds and ships in 44 gallon double poly-lined fiber drums. It is a dark orange/red powder that turns fluorescent green/greenish-yellow when dissolved in an alkaline solution. We are the only U.S. manufacturer of FUSP, and have been consistently supplying the market for over 25 years.

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