GMS stain

Go·mo·ri meth·en·a·mine-sil·ver stain

(gō-mō'rē),
techniques for argentaffin cells: a method using a methenamine-silver solution in combination with gold chloride, sodium thiosulfate, and safranin O; argentaffin granules appear brown-black against a green background; urates: warm sections are treated directly with a hot methenamine-silver solution to produce a blackening of urates; fungi: see Grocott-Gomori methenamine-silver stain; melanin, which reduces silver nitrate.
Synonym(s): GMS stain

GMS stain

A chromic acid, sodium bisulfite stain used in histology and cytology to identify fungi and Pneumocystis jiroveci. The slide is placed in a hot bath for penetration and stains fungi black with sharp margins and a cleared centre.

GMS stain

Gomori-Grocott methenamine silver stain A chromic acid, sodium bisulfite stain used in histology and cytology to identify fungi and Pneumocystis carinii; the slide is placed in a hot bath for penetration and stains fungi black with sharp margins, and a cleared center. See Sealed envelope appearance.
References in periodicals archive ?
An ultrasound (US)-guided percutaneous biopsy of the mass revealed a chronic organizing abscess with filamentous bacteria on GMS stain consistent with an actinomycosis abscess.
Histopathological evaluation of epidural tissue showed predominantly chronic and granulomatous inflammation with numerous large broad based budding organisms seen in black on GMS stain (Figure 2).
Do the black particles on the GMS stain represent fungi?
Although some laboratories additionally perform a periodic acid-Schiff stain for fungi, the GMS stain is preferable, primarily because periodic acid-Schiff provides less contrast between fungi and background debris.
It is also important to note that, on occasion, a poorly performed GMS stain may yield falsely negative results; thus, it is important to check standard tissue controls in every case.
With a GMS stain, Histoplasma yeasts are small, uniform, and oval (Figures 1, F, and 2, B).
Both organisms are highlighted by the GMS stain, whereby the main differentiating features are the uniform size, oval shape, and occasional tapered forms of Histoplasma as opposed to the nonuniform size, round shape, and lack of tapering of Cryptococcus (Figure 2, B and D).
7,52) As with other fungi, the GMS stain reveals more organisms than initially appreciated on H&E-stained sections.