Higher detectability of amyloid with phenol Congo red compared with alkaline Congo red

Introduction Amyloidosis is a heterogeneous group of conditions associated with tissue deposition of insoluble abnormal proteins that damage vital organs. Early diagnosis, when the deposits are minimal, determines the prognosis and requires histological confirmation. The commonly adopted gold standa...

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Main Authors: Marta Legatowicz-Koprowska, Justyna Szczygieł, Małgorzata Mańczak, Ewa Walczak
Format: Article
Language:English
Published: Termedia Publishing House 2024-11-01
Series:Rheumatology
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Online Access:https://reu.termedia.pl/Higher-detectability-of-amyloid-with-phenol-Congo-red-compared-with-alkaline-Congo,192390,0,2.html
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author Marta Legatowicz-Koprowska
Justyna Szczygieł
Małgorzata Mańczak
Ewa Walczak
author_facet Marta Legatowicz-Koprowska
Justyna Szczygieł
Małgorzata Mańczak
Ewa Walczak
author_sort Marta Legatowicz-Koprowska
collection DOAJ
description Introduction Amyloidosis is a heterogeneous group of conditions associated with tissue deposition of insoluble abnormal proteins that damage vital organs. Early diagnosis, when the deposits are minimal, determines the prognosis and requires histological confirmation. The commonly adopted gold standard technique is alkaline Congo red (ACR) staining, though its sensitivity is limited. There is a need for a simple and inexpensive screening method offering a better chance of detecting mini­mal amyloid deposits. The aim of this study was to compare amyloid detectability with ACR and phenol Congo red (PHCR) staining techniques for early detection of minimal deposits. Material and methods We assessed 452 tissue specimens (including adipose tissue, gastrointestinal mucosa, labial salivary gland, myocardium, and bone marrow) from 425 patients with clinically suspected systemic or local amyloidosis, which had been sent to the Pathology Laboratory of the National Institute of Geriatrics, Rheumatology and Rehabilitation in Warsaw. Adjacent sections from each specimen were stained with ACR and PHCR. If amyloid was detected, immunohistochemical typing was conducted. The consistency of the two staining methods was expressed as Cohen’s κ coefficient. Results A total of 169 tissue specimens (37%) yielded positive readings, with 93 cases ACR(+) and PHCR(+); 75 cases ACR(–) and PHCR(+), and 1 case ACR(+) and PHCR(–). The percentage agreement between the staining methods was 83%, with the Cohen’s κ coefficient value of 0.60 (95% CI: 0.52–0.69), which corresponds to moderate agreement according to Fleiss. Additional immunohistochemical amyloid typing, conducted in ACR(–) and PHCR(+) specimens, yielded conclusive results in 82% of cases. Conclusions The use of PHCR staining as a screening method in suspected amyloidosis improves amyloid (light chain, transthyretin, and amyloid A protein) detectability in various tissues. The PHCR staining specificity should be verified via electron microscopy and/or mass spectrometry.
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issn 0034-6233
2084-9834
language English
publishDate 2024-11-01
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series Rheumatology
spelling doaj-art-82842d97a11c49a4b07593fc9b37457e2025-01-27T11:20:37ZengTermedia Publishing HouseRheumatology0034-62332084-98342024-11-0162533834510.5114/reum/192390192390Higher detectability of amyloid with phenol Congo red compared with alkaline Congo redMarta Legatowicz-Koprowska0Justyna Szczygieł1Małgorzata Mańczak2Ewa Walczak3Department of Pathology, National Institute of Geriatrics, Rheumatology and Rehabilitation, Warsaw, PolandDepartment of Cardiomyopathy, Cardinal Wyszynski National Institute of Cardiology, Warsaw, PolandDepartment of Gerontology, Public Health and Education, National Institute of Geriatrics, Rheumatology and Rehabilitation, Warsaw, PolandDepartment of Pathology, National Institute of Geriatrics, Rheumatology and Rehabilitation, Warsaw, PolandIntroduction Amyloidosis is a heterogeneous group of conditions associated with tissue deposition of insoluble abnormal proteins that damage vital organs. Early diagnosis, when the deposits are minimal, determines the prognosis and requires histological confirmation. The commonly adopted gold standard technique is alkaline Congo red (ACR) staining, though its sensitivity is limited. There is a need for a simple and inexpensive screening method offering a better chance of detecting mini­mal amyloid deposits. The aim of this study was to compare amyloid detectability with ACR and phenol Congo red (PHCR) staining techniques for early detection of minimal deposits. Material and methods We assessed 452 tissue specimens (including adipose tissue, gastrointestinal mucosa, labial salivary gland, myocardium, and bone marrow) from 425 patients with clinically suspected systemic or local amyloidosis, which had been sent to the Pathology Laboratory of the National Institute of Geriatrics, Rheumatology and Rehabilitation in Warsaw. Adjacent sections from each specimen were stained with ACR and PHCR. If amyloid was detected, immunohistochemical typing was conducted. The consistency of the two staining methods was expressed as Cohen’s κ coefficient. Results A total of 169 tissue specimens (37%) yielded positive readings, with 93 cases ACR(+) and PHCR(+); 75 cases ACR(–) and PHCR(+), and 1 case ACR(+) and PHCR(–). The percentage agreement between the staining methods was 83%, with the Cohen’s κ coefficient value of 0.60 (95% CI: 0.52–0.69), which corresponds to moderate agreement according to Fleiss. Additional immunohistochemical amyloid typing, conducted in ACR(–) and PHCR(+) specimens, yielded conclusive results in 82% of cases. Conclusions The use of PHCR staining as a screening method in suspected amyloidosis improves amyloid (light chain, transthyretin, and amyloid A protein) detectability in various tissues. The PHCR staining specificity should be verified via electron microscopy and/or mass spectrometry.https://reu.termedia.pl/Higher-detectability-of-amyloid-with-phenol-Congo-red-compared-with-alkaline-Congo,192390,0,2.htmlbiopsydetectionamyloidphenol congo redalkaline congo red
spellingShingle Marta Legatowicz-Koprowska
Justyna Szczygieł
Małgorzata Mańczak
Ewa Walczak
Higher detectability of amyloid with phenol Congo red compared with alkaline Congo red
Rheumatology
biopsy
detection
amyloid
phenol congo red
alkaline congo red
title Higher detectability of amyloid with phenol Congo red compared with alkaline Congo red
title_full Higher detectability of amyloid with phenol Congo red compared with alkaline Congo red
title_fullStr Higher detectability of amyloid with phenol Congo red compared with alkaline Congo red
title_full_unstemmed Higher detectability of amyloid with phenol Congo red compared with alkaline Congo red
title_short Higher detectability of amyloid with phenol Congo red compared with alkaline Congo red
title_sort higher detectability of amyloid with phenol congo red compared with alkaline congo red
topic biopsy
detection
amyloid
phenol congo red
alkaline congo red
url https://reu.termedia.pl/Higher-detectability-of-amyloid-with-phenol-Congo-red-compared-with-alkaline-Congo,192390,0,2.html
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AT justynaszczygieł higherdetectabilityofamyloidwithphenolcongoredcomparedwithalkalinecongored
AT małgorzatamanczak higherdetectabilityofamyloidwithphenolcongoredcomparedwithalkalinecongored
AT ewawalczak higherdetectabilityofamyloidwithphenolcongoredcomparedwithalkalinecongored