red cell agglutination

{{short description|Clumping of red blood cells}}

{{About|the hematologic condition|the use of red cell agglutination as a testing method|hemagglutination}}

File:Red cell agglutination.jpg

In hematology, red cell agglutination or autoagglutination is a phenomenon in which red blood cells clump together, forming aggregates. It is caused by the surface of the red cells being coated with antibodies.{{cite book|last1= Bain|first1=BJ|title=Blood Cells: A Practical Guide|url=https://books.google.com/books?id=dckoCQAAQBAJ|date=20 January 2015|publisher=John Wiley & Sons|isbn=978-1-118-81733-9|edition=5}}{{rp|98}} This often occurs in cold agglutinin disease, a type of autoimmune hemolytic anemia in which people produce antibodies (termed cold agglutinins) that bind to their red blood cells at cold temperatures and destroy them. People may develop cold agglutinins from lymphoproliferative disorders, from infection with Mycoplasma pneumoniae or Epstein–Barr virus, or idiopathically (without any apparent cause). Red cell agglutination can also occur in paroxysmal nocturnal hemoglobinuria{{cite web |url=https://documents.cap.org/documents/2019-hematology-clinical-microscopy-glossary.pdf |title=Blood cell identification |author=Hematology and Clinical Microscopy Committee |work=Hematology and Clinical Microscopy Glossary |publisher=College of American Pathologists |date=2019 |url-status=live |archiveurl=https://web.archive.org/web/20190628144822/https://documents.cap.org/documents/2019-hematology-clinical-microscopy-glossary.pdf |archivedate=2019-06-28 |accessdate=2020-06-25 }}{{rp|13}} and warm autoimmune hemolytic anemia.{{r|Kottke2012|p=88}} In cases of red cell agglutination, the direct antiglobulin test can be used to demonstrate the presence of antibodies bound to the red cells.{{cite journal |last1=Quist |first1=Erin |last2=Koepsell |first2=Scott |title=Autoimmune Hemolytic Anemia and Red Blood Cell Autoantibodies |journal=Archives of Pathology & Laboratory Medicine |volume=139 |issue=11 |pages=1455–8 |year=2015 |pmid=26516943 |doi=10.5858/arpa.2014-0337-RS |doi-access=free }}

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Interference with laboratory tests

Red blood cell aggregates are counted as single cells by the automated analyzers used to run complete blood count tests. This leads to a markedly decreased red blood cell count and hematocrit and markedly elevated mean cell volume and mean cell hemoglobin concentration.{{cite book|last1=Bain|first1=BJ|last2=Bates|first2=I|last3=Laffan|first3=MA|title=Dacie and Lewis Practical Haematology|url=https://books.google.com/books?id=rEPUDAAAQBAJ|date=2017|publisher=Elsevier Health Sciences|edition=12|isbn=978-0-7020-6925-3}}{{rp|32–3}} Red cell agglutination also interferes with routine methods for blood typing and blood compatibility testing, which rely on agglutination reactions. People with red cell agglutination may exhibit spontaneous agglutination reactions during testing, leading to a false positive result.{{cite book|author=Denise M Harmening|title=Modern Blood Banking & Transfusion Practices|url=https://books.google.com/books?id=vxyDDwAAQBAJ|date=30 November 2018|publisher=F.A. Davis|isbn=978-0-8036-9462-0}}{{rp|141,262}} If the causative antibodies are only active at room temperature, the agglutination can be reversed by heating the blood sample to {{convert|37|Celsius|F}}. People with warm autoimmune hemolytic anemia may exhibit red cell agglutination that does not resolve on warming.{{cite book|last1=Kottke-Marchant|first1=K|last2=Davis|first2=B|title=Laboratory Hematology Practice|url=https://books.google.com/books?id=dlZDhbXDuOQC|date=6 June 2012|publisher=John Wiley & Sons|isbn=978-1-4443-9857-1}}{{rp|88}}

References

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{{DEFAULTSORT:Red Cell Agglutination}}

Category:Hematology

{{Abnormal clinical and laboratory findings for blood}}