Nowadays there is a great advance in diagnostic techniques in Gastroenterology. Among them, Chromoendoscopy stands out, a technique that consists in the application of dyes on the digestive mucosa to facilitate and improve the quality of diagnosis, and the staining of the mucosa also allows to visualize it in a more evident way, highlight the characteristics of the lesions already detected, detect abnormal lesions more quickly, since the details of its surface stand out with the staining, besides conferring greater sensitivity and specificity in the diagnosis of dysplasias, metaplasias or carcinoma in the various segments of the digestive tract.


Renylab manufactures a high quality endoscopic line. All dyes are registered with ANVISA and have a Certificate of Good Manufacturing Practices.


  Dyes for Endoscopy



Dye solution used to enhance Barret’s epithelium. The methylene blue when used in the esophagus, allows to confirm the presence of intestinal epithelium specialized in patients with short segments of columnar mucosa, to lift the map of extension and distribution of Barret’s epithelium, to make less likely the diagnosis of Barret’s esophagus, when the segment of mucosa of the terminal esophagus is not colored by this methodology and to orient biopsies to areas of higher risk of dysplasia and adenocarcinoma.


Dye solution used throughout the digestive tract, to highlight the contours of the mucosa, highlighting polyps and small flat lesions, filling folds, crypts, erosions and ulcers. It can be used in multiple situations: to highlight the villous character of Barret’s mucosa and to identify flat areas of high grade dysplasia or carcinoma, to highlight irregularities of gastric mucosa corresponding to areas of metaplasia or dysplasia and in the duodenum to highlight the atrophic aspect of the mucosa. It should be used in the detailed characterization of macroscopic lesions and in the study of high risk neoplastic mucosa without apparent lesions. There is no contraindication to its use and it does not need washing before or after its instillation.


Dye solution usually used in colonoscopy to highlight the contours of the mucosa, highlighting polyps and small flat lesions and filling folds, crypts, erosions and ulcers. It is used for the demarcation of small and multiple lesions of the mucosa as a preoperative resource that facilitates their handling. There is no contraindication to its use and it does not require washing before or after its instillation.



Dye solution of particular interest in the early detection of epidermal adenocarcinoma of the esophagus. The areas of the mucosa that turn yellow or pink after instillation deserve particular attention.

Lugol’s instillation is useful in the early detection of epidermoid carcinomas in the population considered at high risk (individuals with head and neck carcinoma, consumers of alcohol and tobacco in large quantities). In addition, Lugol allows a better definition of the margins of a known lesion, to design other lesional foci in the esophageal mucosa and to evaluate the existence of residual lesion after endoscopic musectomy. For some authors, the great advantage of Lugol is not in its diagnostic power, but in its ability to delimit a lesion. Other authors attribute  Lugol a significant ability to increase the sensitivity to detect high grade dysplasia or carcinoma (from 62% to 96%).

The objective of this guide is to clarify the mechanism of action together with the techniques of application of different dyes and show the various clinical applications that endoscopic dyes have.



The dyes used in Chromoendoscopy have particular characteristics and distinct objectives, being classified as absorption dyes, contrast dyes and reactive dyes.


  Absorption Dyes

Dyes that have this property have the ability to pass to the intracellular environment through absorption or diffusion, when they identify epithelial cells and their constituents. The chemical properties of the dye determine its fixation and its use in several situations.


  Contrast Dyes

Contrast stains have the function of highlighting the contour and topography of the mucosa, since they do not penetrate the intracellular environment.


  Reactive Dyes

Reactive dyes identify the acid producing gastric cells.




Before the chromoendoscopy procedure it is common to make a preparation of the mucosal surface, since it is covered with a variable amount of mucoid material. For this, mucolytic agents are used, which are substances that break and rupture the peptidic bonds of the proteins that constitute the mucus, making it more easily eliminated, because it becomes less viscous.  Ex: Acetylcysteine, dimethyl-polisiloxane, n-acetylcysteine, acetic acid.

Endoscopic dyes can be applied directly through the endoscope channel, using syringes or catheters or through spray, the most commonly used technique. The choice depends on the type of staining and the purpose for which it is applied.

 Table 1.


Dye PropertyColorAction ConcentrationClinical purposeMucosa preparation
Methylene blueAbsortionBlueIt accumulates in

cytoplasm of

mucosal cells.



Barrett’s esophagus and



N-acetilcisteín 10%

Acetic acid 1%




ContrastBlueHighlights the

contours of the

mucosa highlighting

polyps and small

flat lesions,

by filling in

pleats, crypts,

erosions and ulcers.

 0,5%Neoplasic lesions

identified or not

in the stomach and colon.

LugolAbsortionBrownAffinity for

glycogen of epithelial cells

not stratified


 2%epidermoid carcinoma of






morphological of

injuries. Allows

highlight the

contours and better

highlight the

topography of


10%.It can also be

used as

pre operatory resource for

demarcation of

injured areas.




The use of the Chromoendoscopy technique is simple, safe, easy to perform and inexpensive. The careful choice of dyes according to the situations presented allows greater sensitivity and specificity, making the diagnosis more reliable, safe and of higher quality.


Bibliographic References

1- Fennerty MB. Tissue staining. Gastrointestinal endoscopy. Clin N Am 1994;4:297-311.

2- Gostout C. Early lesions: staining magnifying scopes and mucosectomy. Frontiers oftherapeutic endoscopy. Post graduate course. Colonoscopy 1997; 63.

3- Kim C, Fleischer D. Colonic chromoscopy. Gastrointestinal Endoscopy Clinics N.Am. 1997; 4(3): 423-37.

4- Misumi a , ETAL. Role of lugol dye endoscopy in the diagnosis of early esophageal cancer. Endoscopy 1990; 22: 12-6.

5- Ratilal, P.0; Pires, E.C; Deus, J,R; Novais, L.A: Cromoendoscopia: Porquê colorir? GE vol. 9 2002:340-346

6- Canto M. Methylene blue chromoendoscopy for Barrett’s esophagus: Coming soon to your lgl unit? \endoscopy 2001; 54:560-8