title: Sensitivity of Helicobacter pylori detection by Giemsa staining is poor in comparison with immunohistochemistry and fluorescent in situ hybridization and strongly depends on inflammatory activity.
abstract: BACKGROUND
  Conventional stainings (including H&E and special stains like Giemsa) are the most widely applied histopathologic detection methods of Helicobacter pylori (HP).
  
  
  METHODS
  We aimed to compare the diagnostic performance of Giemsa staining with immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) on a monocentric cohort of 2896 gastric biopsies and relate results to histologic alterations in order to find such histopathologic subgroups in which these methods underperform. All cases were categorized regarding presence or absence of chronic gastritis, inflammatory activity, and mucosal structural alterations.
  
  
  RESULTS
  Giemsa revealed 687 cases (23.7%), IHC 795 cases (27.5%), and FISH 788 cases (27.2%) as being HP positive. Giemsa showed significantly lower overall sensitivity (83.3%) compared to IHC (98.8%) and FISH (98.0%). Moreover, the sensitivity of Giemsa dramatically dropped to 33.6% in the nonactive cases. We found that sensitivity of Giemsa strongly depends on HP density and, accordingly, on the presence of activity. Structural alterations (intestinal metaplasia, atrophy, etc.) had only no or weak effect on sensitivity of the three stainings. Both IHC and FISH proved to be equally reliable HP detecting techniques whose diagnostic performance is minimally influenced by mucosal inflammatory and structural alterations contrary to conventional stainings.
  
  
  CONCLUSIONS
  We highly recommend immunohistochemistry for clinically susceptible, nonactive chronic gastritis cases, if the conventional stain-based HP detection is negative. Moreover, we recommend to use IHC more widely as basic HP stain. Helicobacter pylori FISH technique is primarily recommended to determine bacterial clarithromycin resistance. Furthermore, it is another accurate diagnostic tool for HP.
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
authors.forename: Éva
authors.initials: É
authors.lastname: Kocsmár
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
authors.forename: Ildikó
authors.initials: I
authors.lastname: Szirtes
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Kramer
authors.affiliation: 1st Department of Surgery, Semmelweis University, Budapest, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Szijártó
authors.affiliation: 1st Department of Medicine, Péterfy Hospital, Budapest, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Bene
authors.affiliation: Department of Gastroenterology, Ferencváros Health Centre, Budapest, Hungary.
authors.forename: György Miklós
authors.initials: GM
authors.lastname: Buzás
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Kenessey
authors.affiliation: Institute of Pathology, University Medical Centre, Freiburg, Germany.|Tumorbank, Comprehensive Cancer Center Freiburg, University Medical Centre, Freiburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Bronsert
authors.affiliation: Institute of Pathology, University Medical Centre, Freiburg, Germany.
authors.forename: Agnes
authors.initials: A
authors.lastname: Csanadi
authors.affiliation: Institute of Pathology, University Medical Centre, Freiburg, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Lutz
authors.affiliation: Institute of Pathology, University Medical Centre, Freiburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Werner
authors.affiliation: Tumorbank, Comprehensive Cancer Center Freiburg, University Medical Centre, Freiburg, Germany.|Clinic for Surgery, UKSH Campus Lübeck, Lübeck, Germany.
authors.forename: Ulrich Friedrich
authors.initials: UF
authors.lastname: Wellner
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Kiss
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Schaff
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
authors.forename: Gábor
authors.identifier: http://orcid.org/0000-0002-6921-8978
authors.initials: G
authors.lastname: Lotz
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006651:Histocytochemistry / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods
keywords: 
  FISH
  ; 
  Helicobacter pylori
  ; chronic gastritis; diagnostic algorythm; immunohistochemistry; sensitivity