Glutamine synthetase by IHC

Alphabetical Test listing

Glutamine synthetase by IHC-12376 - Technical only, 12379 - Technical & interpretation

Glutamine synthetase by IHC
12376 - Technical only, 12379 - Technical & interpretation

All IHC stains will include a positive control tissue

  • In normal liver, GS is present in the centrilobular regions of the liver, usually around the central veins
  • In FNH of the liver, GS is present in large groups of hepatocytes, in an anastomosing pattern, typically around hepatic veins (referred to as a geographic or "map-like" pattern)
  • HA show no staining, focal staining of hepatocytes around central veins, or patchy staining at the periphery (non-uniform and non-intense)
  • Diffuse GS staining is seen in 13-70% of early hepatocellular carcinomas (HCC)
  • High-grade dysplastic nodules (HGDN) are either GS negative, or show patchy positive staining for GS

Submit a formalin-fixed, paraffin-embedded tissue


Formalin-fixed, paraffin-embedded (FFPE) tissue block


FFPE tissue section mounted on a charged, unstained slide


Ambient (preferred)

  • Unlabeled/mislabeled block
  • Insufficient tissue
  • Slides broken beyond repair
AHL - Immunohistochemistry
Mo - Fr
1 - 2 days

Immunohistochemical staining and microscopic examination


If requested, an interpretive report will be provided



  • Glutamine synthetase (GS) is an enzyme that converts glutamate and ammonia to glutamine
  • GS can be used in a panel with serum amyloid A and beta catenin to help differentiate between hepatic adenomas (HA) and focal nodular hyperplasia (FNH)

Staining pattern

  • Strong cytoplasmic staining


  1. Shafizadeh N et al: Diagnosis of well-differentiated hepatocellular lesions: role of immunohistochemistry and other ancillary techniques. Adv Anat Pathol 2011;18:438-445).
  2. Joseph NM et al: Diagnostic utility and limitations of glutamine synthetase and serum amyloid-associated protein immunohistochemistry in the distinction of focal nodular hyperplasia and inflammatory hepatocellular adenoma. Modern Pathology (2014) 27, 62-72; doi:10.1038/modpathol.2013.114.
88342 - 1st stain
88341 - each additional stain