Sodium Fluorescein
Sodium fluorescein is a fluorescent xanthene dye that emits a yellow-green color under blue (490 nm) or ultraviolet light, visible even at very low concentrations in urine. In GU practice it has a niche role as an IV ureteral-identification agent and as an intravesical leak-detection dye — filling the gap left by indigo carmine shortages and serving as a low-cost alternative to NIR fluorophores in centers without NIR imaging.[1]
Pharmacology
| Property | Value |
|---|---|
| Class | Xanthene fluorescent dye |
| Color | Yellow-green (visible), intensifies under blue/UV light |
| Route | IV or intravesical |
| Renal excretion | Rapid glomerular filtration → visible in urine within 5–15 minutes of IV dose |
| Duration | 30–60 minutes of visible urinary fluorescence |
| FDA approval | Ophthalmic use (1960s); IV use for retinal angiography and, by extension, intraoperative ureteral visualization |
GU Applications
1. IV ureteral identification during MIS / open pelvic surgery
- 25–50 mg IV (diluted) produces visible yellow-green urinary efflux within 5–15 minutes
- Particularly useful when indigo carmine is unavailable and NIR imaging is not in place
- Doyle et al. 2015 Obstet Gynecol established feasibility in gynecologic surgery after the indigo carmine shortage[2]
2. Intravesical cystoscopic leak testing
- Dilute fluorescein (10 mg in 100 mL saline) instilled into the bladder
- Visible leak at urethroplasty or vesicourethral anastomosis under white or cobalt-blue light
- An alternative to methylene blue for surgeons who prefer the yellow-green color that contrasts more distinctly against blue surgical drapes
3. Perfusion / angiography (limited GU use)
- Widely used in ophthalmology for retinal angiography
- Occasional intraoperative use for flap perfusion assessment in plastic surgery
- Rare in GU reconstruction (ICG preferred for perfusion)
Dosing
- IV ureteral identification: 25–50 mg IV (dilute in 10 mL saline, give slowly)
- Intravesical leak test: 10–25 mg diluted in 100 mL saline
Adverse Events
- Skin yellowing — transient
- Yellow urine — expected, resolves in 24 hours
- Nausea, vomiting — occasional at higher doses
- Anaphylactoid reactions — rare but reported at retinal-angiography doses
- False elevations of urinary bilirubin and glucose on dipstick assays — warn the lab
Sodium Fluorescein vs. Indigo Carmine vs. Methylene Blue
| Feature | Sodium Fluorescein | Indigo Carmine | Methylene Blue |
|---|---|---|---|
| Color | Yellow-green | Blue-violet | Deep blue |
| Visible in urine | Yes (enhanced under UV/blue) | Yes | Yes |
| Best use | Alternative to indigo carmine when unavailable | Ureteral ID (historical) | Fistula / orifice / anastomotic leak |
| Availability | Consistent | Intermittent shortages | Consistent |
| Cost | Low | Low | Very low |
| Need for special imaging | Enhanced by blue filter (optional) | None | None |
See Also
References
1. Doyle PJ, Lipetskaia L, Duecy E, Buchsbaum G, Wood RW. Sodium fluorescein use during intraoperative cystoscopy. Obstet Gynecol. 2015;125(3):548–550. doi:10.1097/AOG.0000000000000691
2. Rivard C, Nahum R, Slagle E, Duininck M, Isaksson Vogel R, Teoh D. Evaluation of the use of sodium fluorescein during intraoperative cystoscopy. Obstet Gynecol. 2014;124(4):815–8. doi:10.1097/AOG.0000000000000460