Immunoperoxidase in the interpretation of discordant histologic and urease findings for Helicobacter pylori.
Azure A and methylene blue ("Diff-Quik," DQ) and tissue urease (U) tests are popular methods to diagnose Helicobacter pylori. These tests usually correlate well but sometimes produce discordant results. This study evaluates the DQ and U tests by comparing them with the immunoperoxidase reference method to resolve discordant results. DQ and U tests were performed on gastric biopsies. Results were tabulated as DQ(+)/U(+), DQ(+)/U(-), DQ(-)/U(+), and DQ(-)/U(-). Cases that were DQ(+)/U(+) were recorded as positive and not tested with immunoperoxidase. Cases that had discordant DQ/U results were tested by immunoperoxidase to resolve the discordance. Cases which were negative for both DQ/U were evaluated by immunoperoxidase to confirm the validity of DQ(1-)/U(-). The groups were compared with concordant results (DQ(1-)/U(-) group) and immunoperoxidase versus discordant DQ/U results and immunoperoxidase. There were 56 gastric biopsy specimens. Among all cases, 6 were DQ(+)/U(+). Of the remaining 50 cases, 38 were concordant DQ(-)/U(-), whereas 12 showed discordant DQ/U results. All 38 concordant DQ(-)/U(-) specimens were confirmed negative, 11 discordant DQ/U cases were confirmed negative, and 1 DQ(+)/U(-) specimen was confirmed positive by immunoperoxidase. Comparison of concordant versus discordant results was not statistically significant (P=0.10). Among all discordant DQ and U, 11/12 (92%) were confirmed negative by immunoperoxidase. Thus, both concordant negative results and discordant results can be considered negative. Such interpretation of discordant results might prevent unnecessary additional procedures or treatment.
Whitters
Andrew D
AD
Mount Mercy College, Cedar Rapids, IA 52403, USA.
Carson
Henry J
HJ
Eilers
Stanley G
SG
Bernstein
Neil P
NP
D001399:Azure Stains / Q000378:metabolism; D001706:Biopsy; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D016480:Helicobacter pylori / Q000201:enzymology / Q000302:isolation & purification*; D006801:Humans; D007150:Immunohistochemistry; D008751:Methylene Blue / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014510:Urease / Q000378:metabolism*; D014966:Xanthenes / Q000378:metabolism
D001399:Azure Stains; C067461:Diff Quik; D014966:Xanthenes; D009195:Peroxidase; D014510:Urease; D008751:Methylene Blue